Conservation Genetics  is a bimonthly  peer-reviewed   scientific  journal covering all areas of  conservation genetics . It was originally established in 2000 by  Kluwer Academic Publishers , [ 1 ]  and is currently published by  Springer Science+Business Media . The  editor-in-chief  is A. Rus Hoelzel ( University of Durham ). According to the  Journal Citation Reports , the journal has a 2022  impact factor  of 2.2 [ 2 ]


Conservation Genetics Resources  is a quarterly  peer-reviewed scientific journal  covering methodological improvements, computer programs, and the development of  genomic  resources related to  conservation genetics . It was established in 2009 and is published by  Springer Science+Business Media . The  editor-in-chief  is Benoit Goossens ( Cardiff University ). According to the  Journal Citation Reports , the journal has a 2015  impact factor  of 0.446. [ 1 ]


Critical Reviews in Eukaryotic Gene Expression  is a quarterly  scientific journal  published by  Begell House  publishing reviews on topics related to  gene regulation , organization, and structure within contexts of biological control and diagnosis/treatment of disease.


According to the  Journal Citation Reports , its 2018  impact factor  is 1.841. The  editors-in-chief  are  Gary S. Stein ,  Janet L. Stein , and  Jane B. Lian .


Current Genomics  is a  peer-reviewed   scientific journal  covering all aspects of  genomics . It was established in 2000 with  Stefan M. Pulst  as founding editor-in-chief and is  published by  Bentham Science Publishers .
The  editor-in-chief  is Christian Néri ( INSERM ).


The journal is abstracted and indexed in:


According to the  Journal Citation Reports , the journal has a 2019  impact factor  of 2.630. [ 5 ]


Redirect to:


Cytogenetic and Genome Research  is the name of a  peer-reviewed   scientific journal  that was established in 1962. It was published previously under the names  Cytogenetics  (1962–1972) and  Cytogenetics and Cell Genetics  (1973–2001).


The journal is abstracted and indexed in  Current Contents /Life Sciences,  PubMed / MEDLINE ,  EMBASE/Excerpta Medica , CAB Abstracts, Scopus, Biological Abstracts, BIOSIS Previews, Journal Citation Reports (Science Edition), Science Citation Index, Science Citation Index Expanded, Web of Science and Zoological Record
. According to the  Journal Citation Reports , the journal has a 2014  impact factor  of 1.561. [ 1 ]


Epigenetics  is a monthly  peer-reviewed   scientific journal  covering research pertaining to  epigenetics . It was established in 2006 and published by  Landes Bioscience , until this company was acquired by  Taylor & Francis  in 2014. It is the official journal of the  Epigenetics Society  (formerly the DNA Methylation Society). The  editor-in-chief  is  Manel Esteller  ( University of Barcelona ).


According to the  Journal Citation Reports , the journal has a 2017  impact factor  of 4.918, ranking it 51st out of 292 journals in the category "Biochemistry & Molecular Biology" [ 1 ]  and 30th out of 171 in the category "Genetics & Heredity". [ 2 ]


Epigenetics & Chromatin  is a peer-reviewed open access scientific journal published by BioMed Central that covers the biology of epigenetics and chromatin.


Epigenetics & Chromatin  is a peer-reviewed open access scientific journal that publishes research related to epigenetic inheritance and chromatin-based interactions. First published in 2008 by  BioMed Central , its overall aim is to understand the regulation of gene and chromosomal elements during the processes of  cell division ,  cell differentiation , and any alterations in the environment. To date, 13 volumes have been published. [ 1 ]


As of October 2020, there has been over 340,000 downloads and over 750  Altmetric  mentions. [ 2 ]


According to  Journal Citation Reports , it received an  impact factor  of 4.237 [ 3 ]  in 2019. Its current  SCImago Journal Rank  is 2.449. [ 4 ]


Its 2-year and 5-year citation impact factor is 4.237 [ 3 ]  and 4.763, [ 3 ]  respectively. Its Source Normalized Impact per Paper (SNIP) is 0.896. [ 4 ]


Its current Journal Authority Factor (JAF) is 111.5. [ 5 ]


Current submission guidelines are as follows:


Submitters must ensure that Epigenetics & Chromatin is the most suitable journal for the proposed article in addition to understanding of the costs, funding options, and copyright agreement associated with submission. Accuracy and readability of the manuscript must also be considered. [ 7 ]


The manuscript must follow all formatting rules which authors must read, understand and accept. [ 7 ]


Authors should review the peer-review policy. Authors should also be familiar with the process of manuscript transfers to a different journal, as well as how to promote the publication. [ 7 ]


On average, it takes 53 days to reach a decision for reviewed manuscripts and 35 days for all manuscripts. The process of acceptance takes an average of 112 days after submission. After acceptance, it takes an average of 16 days for an article to be published. [ 7 ]


After successful publication in Epigenetics & Chromatin, articles are also included in: [ 8 ]


As of October 2020, the most accessed articles are: [ 19 ]


G3: Genes, Genomes, Genetics  (also styled as  G3: Genes | Genomes | Genetics ) is a  peer-reviewed   open-access   scientific journal  that focuses on rapid publication of research in the fields of  genetics  and  genomics . It is published by the  Genetics Society of America  and was established in 2011. The journal is abstracted and indexed in  MEDLINE  and the  Science Citation Index Expanded . The founding  editor-in-chief  is  Brenda Andrews  ( University of Toronto ).


Gene  is a  peer-reviewed   scientific journal  in  genetics  and  molecular biology , focusing on the  cloning ,  structure ,  function , as well as the biomedical and biotechnological importance of  genes . The scope of the journal includes all biological organisms including viruses, prokaryotes, and eukaryotes. It is organized into topics, which include Human Genetics, Cancer Genetics, Neurogenetics, Animal Genetics, Genome Editing, Molecular Ecology, Plant Genetics, Parasitology and Virology, as well as Microbiology.


The journal is part of the Gene Family of journals and was established in 1976. It is published by  Elsevier  and the  editor-in-chief  is Marianna Kruithof-de Julio ( University of Bern ) The Gene Family of journals comprises the journals  Gene, Gene Reports, Human Gene,  and  Plant Gene . According to the  Journal Citation Reports , the journal has a 2022  impact factor  of 3.5. [ 1 ]


The journal's first issue was published in 1976 by Elsevier/North-Holland Biomedical Press.  Gene  was first intended to focus on recombination processes of genes and the properties of reconstructed genes and genomes, according to a letter written by Waclaw Szybalski in the first issue. [ 2 ]  Over the years, subspecialized publications on human and plant genetics, as well as a companion journal  Gene Reports , which focuses on the regulation, expression, and evolution of genes and genetic material across a broad range of biological contexts have been split off.


Genes  is a quarterly  peer-reviewed   open access   scientific journal  that is published by  MDPI . The  editor-in-chief  is J. Peter W. Young ( University of York ). [ 1 ]  It covers all topics related to  genes ,  genetics , and  genomics .


Genes & Development  is a  peer-reviewed   scientific journal  covering  molecular biology ,  molecular genetics ,  cell biology , and  development . It was established in 1987 and is published twice monthly by  Cold Spring Harbor Laboratory Press  in association with  The Genetics Society . [ 1 ]


According to the  Journal Citation Reports , the journal has a 2012  impact factor  of 12.44, ranking it 14th out of 181 journals in the category "Cell Biology", [ 2 ]  third out of 40 journals in the category "Developmental Biology", [ 3 ]  and 7th out of 158 journals in the category "Genetics & Heredity". [ 4 ]  Over 1999–2004, the journal was ranked fifth in the "Molecular Biology and Genetics" category according to  ScienceWatch , with an average of 47 citations per paper. [ 5 ]  All issues are available online via the journal website as  PDFs , with a text version additionally available from August 1997. Content over 6 months old is freely available.


Since 1989, the  editor-in-chief  has been  Terri Grodzicker  ( Cold Spring Harbor Laboratory ). [ 6 ]


Genes & Immunity  is a  peer-reviewed   scientific journal  covering the intersection between  immunology  and  genetics . It was established in 1999 and is published eight times per year by  Springer Nature . The  editor-in-chief  is Prof. Abhishek D. Garg ( KU Leuven ). [ 1 ]  According to the  Journal Citation Reports , the journal has a 2023  impact factor  of 5.0, ranking it 47th out of 181 journals in the category "Immunology" and 26th out of 191 in the category "Genetics & Heredity". [ 2 ]


This article about an  immunology   journal  is a  stub . You can help Wikipedia by  expanding it .


Genesis: The Journal of Genetics and Development  (often styled  genesis ) is a  peer-reviewed   scientific journal  of  genetics  and  developmental biology . It was established as  Developmental Genetics  in 1979 and obtained its current title in 2000. In addition to  original research  articles, the journal also publishes  letters to the editor  and technology reports relevant to the understanding of the functions of  genes . The  editor-in-chief  is  Sally A. Moody  ( George Washington University ).


According to the  Journal Citation Reports , the journal has a 2020  impact factor  of 2.487, ranking it 22nd out of 41 journals in the category "Developmental Biology" [ 1 ]  and 118th out of 176 journals in the category "Genetics & Heredity". [ 2 ]


Genetic Testing and Molecular Biomarkers  is a monthly  peer reviewed   scientific journal  published by  Mary Ann Liebert, Inc.  The  editor-in-chief  is  Garth Ehrlichs . The journal covers  genetic testing research  along with associated ethical, legal, social, and economic issues. Related genetic testing coverage includes risk assessment, genetic counseling, carrier detection, novel instrumentation, and  cytogenetics . [ 1 ]  It is the official journal of Genetic Alliance. [ 1 ] [ 2 ]


This journal is indexed and abstracted by the following services: [ 1 ]


Genetica  is a  peer-reviewed   scientific journal  covering research in  genetics  and  evolutionary biology . It was established in January 1919 by  Kluwer Academic  (which later merged into Springer) and originally published articles in English, Dutch, French, and German. Publication was suspended from 1944 to 1946. [ 1 ]  The journal allows  self-archiving  and  authors can pay  extra for  open access . The  editors-in-chief  are Pierre Capy ( French National Centre for Scientific Research ,  Gif-sur-Yvette ) and Ronny C. Woodruff ( Bowling Green State University ).


According to the  Journal Citation Reports , the journal has a 2011  impact factor  of 2.148. [ 2 ]


Genetics  is a monthly  scientific journal  publishing investigations bearing on  heredity ,  genetics ,  biochemistry  and  molecular biology . Genetics is published by the  Genetics Society of America . It has a  delayed open access  policy, and makes articles available online without a subscription after 12 months have elapsed since first publication. Since 2010, it is published online-only. [ 1 ]   George Harrison Shull  was the founding editor of  Genetics  in 1916.


The  Genetics and Molecular Research Journal  is a  peer-reviewed   open-access   scientific journal  in the fields of  biology  and  medicine , edited and published monthly in the fields of  genetics ,  molecular biology ,  proteomics ,  genomics  and evolution. The journal was listed on  Beall's list  before it was taken down in 2017. [ 1 ]  A  hijacked journal  was also setup at  geneticsmr.org  by the  Pulsus Group , unlike the legitimate  geneticsmr.com  operated by  FUNEPC-RP . [ 2 ]


According to the  Journal Citation Reports , the journal has a 2016  impact factor  of 0.765. [ 3 ]


The journal was established in 2002 by  Francisco A. Moura Duarte  and its honorary editor is  Pedro Henrique Saldanha .


This article about a  general medical journal  is a  stub . You can help Wikipedia by  expanding it .


This Brazilian science article is a  stub . You can help Wikipedia by  expanding it .


Genetics Research  is an  open access ,  peer-reviewed   scientific journal  covering all aspects of human and animal genetics, reporting key findings on genomes, genes, mutations and molecular interactions, extending out to developmental, evolutionary, and population genetics as well as ethical, legal and social aspects. It was established in 1960 as  Genetical Research , obtaining its current name in 2008. The founding  editor-in-chief  was Eric C.R. Reeve ( University of Edinburgh ). [ 1 ]


It is published by  Cambridge University Press  and the editor-in-chief is  Marc Tischkowitz  ( University of Cambridge ). According to the  Journal Citation Reports , the journal has a 2017  impact factor  of 1.059, ranking it 149th out of 171 journals in the category "Genetics & Heredity". [ 2 ]


The journal has published papers from such renowned researchers as  Mary Lyon  (of  Lyonisation ), [ 3 ]   Charlotte Auerbach , [ 4 ]  and  John Maynard Smith , author of Genetics Research's most cited paper,  The hitch-hiking effect of a favourable gene .


Genetics Selection Evolution   (known as GSE, and abbreviated with Genet. Sel. Evol.)  is a bimonthly online-only  peer-reviewed   scientific journal  covers original research on all aspects of  genetics  and selection in domestic animal species and other species providing results of immediate interest for farm animals' genetics.


It was established in 1969 as the  Annales de Génétique et de Sélection Animales . It was renamed to  Genetics, Selection, Evolution  in 1983 and to its current name in 1989. Since January 2009, it has been published as an  open access  journal by  BioMed Central . It is owned by the  Institut national de recherche pour l'agriculture, l'alimentation et l'environnement  (INRAE), of which it is the official journal. [ 1 ] [ 2 ] [ 3 ]  The  editors-in-chief  are Didier Boichard (INRAE, France), Jack Dekkers ( Iowa State University, United States of America ), Helene Hayes (INRAE, France), and Mario Calus ( Wageningen University , the Netherlands). According to the  Journal Citation Reports , the journal has a 2019  impact factor  of 3.950 (2 years IF) and 4.017 (5 years IF).


Genome , formerly known as the  Canadian Journal of Genetics and Cytology  (1959–1986), is a monthly  peer-reviewed   scientific journal  that published since 1959 by  NRC Research Press .  Genome  prints articles in the fields of  genetics  and  genomics , including  cytogenetics ,  molecular  and  evolutionary genetics ,  population genetics , and  developmental genetics .  Genome  is affiliated with the Canadian Society for Molecular Biosciences, and is co-edited by  Melania Cristescu  of  McGill University  and Lewis Lukens of  University of Guelph . [ 1 ]


Genome Biology  is a  peer-reviewed   open access   scientific journal  covering research in  genomics . It was established in 2000 and is published by  BioMed Central . The  chief editor  is currently Andrew Cosgrove ( BioMed Central , New York).


According to the  Journal Citation Reports , the journal has a 2019  impact factor  of 10.806. [ 7 ]


Genome Biology and Evolution  is a monthly  peer-reviewed   open access   scientific journal  published by  Oxford University Press  on behalf of the  Society for Molecular Biology and Evolution . It covers research on the interface between  evolutionary biology  and  genomics . [ 1 ]  According to the  Journal Citation Reports , the journal has a 2022  impact factor  of 3.3. [ 2 ]


Genomics  is a  peer-reviewed   scientific journal  in  genomics , publishing articles on topics such as  comparative genomics ,  functional genomics ,  association studies ,  regulatory DNA elements , and  genetics  on a genome-wide scale. [ 1 ] [ 2 ]  The journal was established in September 1987. [ 3 ]


GigaByte  is a  peer-reviewed   open-science   journal  published by GigaScience Press since 2020. [ 1 ]  It focuses on short, focused, data-driven articles describing and sharing open research data sets and software. [ 2 ]  Using an exclusively  XML-based  publishing system that automates the production process to make it simple to change views, languages and embed interactive content, in 2022 it won the  ALPSP Award  for Innovation in Publishing. [ 3 ]


In order to host the large data-sets the journal covers, like its sister journal  GigaScience  it uses its own in-house  disciplinary repository :  GigaDB . [ 4 ]


The journal is abstracted and indexed by  PubMed /PMC/ DOAJ  and  CNKI .


Hereditas  (not to be confused with another journal called  Heredity ) is a  scientific journal  concerning  genetics .  It has been published since 1920 by the Mendelska sällskapet i Lund (Mendelian Society of Lund). In its long history it has published important papers in the field of genetics, including the first discovery of the correct human chromosome count by  Joe Hin Tijo  and  Albert Levan  in 1956. [ 1 ]  In the post-genomic era, the scope of  Hereditas  has evolved to include any research on genomic analysis.


In 2005,  Hereditas  changed from a traditional subscription-based journal to become an  open access , web based and author funded journal. By the end of 2014, Hereditas terminated its activity with Wiley Publishers. In May 2015  Hereditas  was re-launched and became part of the portfolio of the open access publisher  Biomed Central (BMC) , now owned by  Springer Nature .


It is indexed by BIOSIS, DOAJ, MEDLINE, Science Citation Index, and Scopus. The impact factor (IF) of 2021 is 3.4.


Editors-in-chief (EiC): Robert Larsson (1920–1954), Arne Müntzing (1955–1977), Arne Lundqvist (1978–1988), Karl Fredga and Arne Lundqvist (1989–1996), Ulf Gyllensten (1996–2001), Anssi Saura (2002-2011), Stefan Baumgartner (2012 - 2023), Yongyong Shi (2016 -, in parallel to Baumgartner). Ramin Massoumi (2024-, in parallel to Yongyong Shi)


This article about a  biology   journal  is a  stub . You can help Wikipedia by  expanding it .


Heredity  is a monthly  peer-reviewed   scientific journal  published by  Nature Portfolio . It covers  heredity  in a biological sense, i.e.  genetics . The journal was founded by  Ronald Fisher  and  C. D. Darlington  in 1947 and is the official journal of  The Genetics Society . From 1996 the publishing was taken over by Nature Portfolio. The  editor-in-chief  is  Sara Goodacre . [ 1 ]


According to the  Journal Citation Reports , the journal has a 2021  impact factor  of 3.832, ranking it 61st out of 173 journals in the category "Ecology", [ 2 ]  19th out of 51 journals in the category "Evolutionary Biology", [ 3 ]  and 79th out of 175 journals in the category "Genetics & Heredity". [ 4 ]


Human Heredity  is a  peer-reviewed   scientific journal  covering all aspects of  human genetics . It was established in 1948 as  Acta Genetica et Statistica Medica , obtaining its current name in 1969. It is published eight times per year by  Karger Publishers  and the  editor-in-chief  is  Pak Sham  ( University of Hong Kong ). According to the  Journal Citation Reports , the journal has a 2017  impact factor  of 0.542. [ 1 ]


Human Molecular Genetics  is a semimonthly  peer-reviewed   scientific journal  published by  Oxford University Press . It covers all topics related to  human molecular genetics . In addition, two "special review" issues are published each year. The  editor-in-chief  is Charis Eng ( Case Western Reserve University ). The journal was established in 1992.


According to the  Journal Citation Reports , the journal has a 2020  impact factor  of 6.150. [ 1 ]


Immunogenetics  is a  peer-reviewed   scientific journal  covering  immunogenetics , the branch of  medical research  that explores the relationship between the  immune system  and  genetics . This journal publishes original research papers, brief communications and reviews in: immunogenetics of cell interaction, immunogenetics of tissue differentiation and development, phylogeny of  alloantigens  and of  immune response , genetic control of immune response and disease susceptibility, and genetics and biochemistry of alloantigens. [ 1 ]


Immunogenetics was first published yearly starting in December 1974 and then monthly since May 1981. [ 2 ]  It has an impact factor of 2.621 according to the Thomson Reuters 2019  Journal Citation Reports . The current editor-in-chief is Ronald E. Bontrop professor of Theoretical Biology and Bioinformatics at Utrecht University.


Immunogenetics is a  hybrid open-access journal  through the Springer Open Choice option.


The  Journal of Biosocial Science  is a bimonthly  peer-reviewed   scientific journal  covering the intersection of  biology  and  sociology . It was the continuation of  The Eugenics Review , published by the  Galton Institute  from 1909 till 1968. It obtained its current name in 1969, with volume numbering re-starting at 1, and switched publishers to  Cambridge University Press . The  editor-in-chief  is Dr Alejandra Núñez-de la Mora ( Universidad Veracruzana ).


According to the  Journal Citation Reports , the journal has a 2021  impact factor  of 2.148. [ 9 ]


In 2006, the journal published a controversial study [ 10 ]  arguing that  Ashkenazi Jews  are more intelligent than other ethnic groups as a result of human evolution. [ 11 ] [ 12 ] [ 13 ]


The  Journal of Genetics  is a  peer-reviewed   scientific journal  in the field of  genetics  and  evolution . It was established in 1910 by the  British  geneticists  William Bateson  and  Reginald Punnett  and is one of the oldest genetics journals. [ 1 ]  It was later edited by  J.B.S. Haldane , who emigrated to India in 1957, and continued publishing the journal from there.


On Haldane's death in 1964, his second wife  Helen Spurway  continued to publish the journal with  Madhav Gadgil ,  H. Sharat Chandra , and  Suresh Jayakar  as editors until Spurway died in 1977 and the journal ceased publication. With the permission of  Naomi Mitchison , Haldane's sister, it was revived in 1985 and has been published by the  Indian Academy of Sciences , currently in collaboration with  Springer Science+Business Media , since then. All volumes published between 1910 and 1994 (vol. 1-73) are available free on the website of the Indian Academy of Sciences. [ 2 ]


According to the  Journal Citation Reports , the journal has a 2019  impact factor  of 0.993. [ 3 ]


It adopted the "Continuous Article Publication" (CAP) mode from January 2019. [ 4 ]


The  Journal of Genetics and Genomics  (sometimes abbreviated  JGG ) is a monthly  peer-reviewed   scientific journal  covering the fields of  genetics  and  genomics . It was established in 1974 as  Acta Genetica Sinica , obtaining its current name in 2007. It is published by  Elsevier  and the  editor-in-chief  is Jianru Zuo ( Institute of Genetics and Developmental Biology Chinese Academy of Sciences ). According to the  Journal Citation Reports , the journal has a 2022  impact factor  of 5.9. [ 1 ]


The  Journal of Heredity  is a  peer-reviewed   scientific journal  concerned with  heredity  in a biological sense, covering all aspects of  genetics . It is published by  Oxford University Press  on behalf of the  American Genetic Association .


The trends in topics that have been published in the journal reflect the history of the discipline of genetics. [ 1 ]  Early issues included many papers on  eugenics , particularly under the editorial leadership of the journal's first two  editors-in-chief , Paul Popenoe and R. C. Cook. Emphasis on eugenics in the journal declined throughout the 1940s and 1950s as support for the topic waned in the scientific community and the general public; when Cook's daughter, Barbara Kuhn, took over as editor in 1962 after her father's 40-year service, "...the subject of eugenics was essentially dropped." [ 1 ]


Early topics of interest included comparative color inheritance in mammals (as explored in a series of articles that served as precursors to work applying enzyme kinetics to developmental genetics), determination of the number of human chromosomes, genetic histories of a number of types of livestock (including hybridization of cattle with American bison, [ 1 ]  the discovery of salivary chromosomes in  Drosophila , and "A remarkable paper by Prokofyeva-Belgovskaya, pointing out a difference between mother and daughter chromosomes in binucleate cells. This foreshadowed modern work in intestinal tumors in which there are differences between cells containing the template DNA and those with copies." [ 1 ]


The following persons have been editor-in-chief of the journal:


The journal publishes articles in the following categories:


and on invitation:


Mammalian Genome  is a  peer-reviewed   journal  that publishes research and review articles in the fields of  genetics  and  genomics  in mouse, human and related organisms. [ 1 ] [ 2 ]  As of July 2009 its editors-in-chief are Joseph H. Nadeau and  Stephen D. M. Brown . [ 3 ]   Mammalian Genome  has been published by  Springer  since the journal was launched in 1991, and is the official journal of the  International Mammalian Genome Society . [ 4 ]  In 1998 the journal  Mouse Genome  was merged into  Mammalian Genome . [ 5 ]  Authors are allowed to  self-archive , [ 6 ]  and can pay extra for  open access  for an article. [ 7 ]


Mitochondrial DNA  is an  academic journal  that publishes  review articles  on the current and developing technologies around mitochondrial DNA research and discovery. It is published by  Informa Healthcare .


Coverage includes:


Previously published under the title  DNA Sequence  (Vols 1–19.3),  Mitochondrial DNA  accepts original high-quality reports based on mapping, sequencing and analysis of mitochondrial DNA and RNA. Descriptive papers on DNA sequences from mitochondrial genomes, and also analytical papers in the areas of population genetics, medical genetics, phylogenetics and human evolution that use mitochondrial DNA as a source of evidence for studies will be considered for publication. The editorial board will also consider manuscripts that examine population genetic and systematic theory that specifically address the use of mitochondrial DNA sequences, as well as papers that discuss the utility of mitochondrial DNA information in medical studies and in human evolutionary biology.


Rob DeSalle  (American Museum of Natural History) is the  editor-in-chief  of  Mitochondrial DNA . [ 1 ]


Questions about the journal can be addressed to both the editor-in-chief and the  managing editor ,   Sergios-Orestis Kolokotronis  (Barnard College, Columbia University).


Mitochondrial DNA  has published so far two special free-access issues on  DNA Barcoding :


Mitochondrial DNA  publishes WebFirst—a method of publishing where a journal is made available as multiple online issues throughout the year, with a single print archive copy of the entire volume being published at the end of the year. Access to the online version is included in all subscriptions.


Mitochondrial DNA  is abstracted in:  Current Contents /Life Sciences;  Science Citation Index ; Research Alert;  Current Awareness in Biological Science (CABS) ;  Chemical Abstracts ;  Index Medicus ;  MEDLINE ;  GenBank ;  Scopus ;  Zoological Record .


Molecular Cytogenetics  is a continuous,  open access ,  peer-reviewed  journal covering research into  cytogenetics  and its applications throughout the fields of biology and medicine. It was established in 2008 and is published by  BioMed Central . The  editors-in-chief  are Thomas Liehr ( Institute of Human Genetics ), Henry Heng ( Wayne State University School of Medicine ), and Yuri Yurov ( National Research Center of Mental Health ). According to the  Journal Citation Reports , the journal has a 2015  impact factor  of 1.506. [ 1 ]


Molecular Genetics and Metabolism  is a  peer-reviewed   academic journal  published by  Academic Press .  It is the official journal of the  Society for Inherited Metabolic Disorders .


The editor is E.R.B. McCabe.


The journal is abstracted/indexed in:


This article about a  biochemistry   journal  is a  stub . You can help Wikipedia by  expanding it .


Molecular Therapy  is a scientific journal, published by  Cell Press , that aims to develop and explore "molecular and cellular therapeutics to correct genetic and acquired diseases". [ 1 ]


The founder of the journal and its Editor-in-Chief in the first five years was  Inder Verma . [ 2 ]


Mouse News Letter (MNL)  was a bulletin of mouse genetics information published from 1949 to 1998. In 1990 Mouse News Letter  changed its name to Mouse Genome which merged with the journal  Mammalian Genome  in 1998. Mouse News Letter now exists as a company, Mouse News Letter Ltd, which promotes the science of Genetics and provides funds to enable younger scientists to attend Genetics Conferences. “To survey the history of the Mouse News Letter is to see the history of mouse genetics unfold.” So wrote  Mary F Lyon  in 1997. [ 1 ]


At the Eighth International Genetics Congress in 1948 eminent geneticists  Douglas Falconer ,  R.A.Fisher ,  Salome Gluecksohn-Waelsch ,  Hans Grüneberg  and  Paula Hertwig  agreed that investigators working on mouse genetics and development needed a regular information bulletin. Hence, the first issue of Mouse News Letter edited by  L.C.Dunn  and Salome Gluecksohn-Waelsch was published in June 1949. [ 2 ] [ 3 ] [ 4 ]  It comprised lists of inbred strains, mutant stocks and new mutants. Toby Carter, who had been one of R.A. Fisher's students, took over as editor until 1956. The Mouse News Letter logo, a circular mouse emblem, first appeared on the cover of the third issue reaching its final form in Mouse News Letter number 4.


Although Mouse News Letter became more sophisticated over the years,  many of the basic elements seen in the first issues were retained throughout. These included lists and maps of mouse genes and mutants, information on inbred strains, and brief reports of useful results that did not merit a full paper.  The first gene list appeared in 1951, containing  only 125 genes. The first linkage map, comprising 15 “linkage groups” with 58 loci was published in MNL in 1953. The database underlying the linkage map was maintained for many years by Margaret Green [ 5 ]  and subsequently by  Muriel Davisson  and Tom Roderick and colleagues. [ 6 ]  On behalf of the Committee for Standardised Genetic Nomenclature for Mice, [ 7 ] [ 8 ] [ 9 ]  nomenclature rules for naming mouse genes and mouse strains were published. MNL was issued twice a year and was free until 1972 when subscription fees were introduced. Lists of inbred strains appeared from very early days but between 1958 and 1984 were issued as a separate entity “Inbred Strains of Mice” every two years as a supplement. MNL was edited by Mary Lyon from 1956-1972 and then by Tony Searle until 1982.


In 1986, during Jo Peters’ time as editor, MNL became a formal publication of genetic information published by  Oxford University Press . Then, for the first time, contributions could be quoted without seeking permission from the author. The Nomenclature Committee formed the Editorial Board. The number of issues per year increased from two to three with the third one being an “Inbred Strains” issue edited by  Michael Festing . This replaced Inbred Strains of Mice. The journal was run by a company Mouse News Letter Ltd, limited by guarantee and with charitable status.
Over the years, with the inexorable increase in genetic information, MNL also grew and the size and variety of lists and maps published increased greatly. In keeping with the then new field of recombinant DNA work, lists of restriction fragment length polymorphisms (RFLPs) and probes and clones were included. [ 10 ]   The new maps ranged from a Mouse Chromosome Atlas [ 11 ]   that showed man-mouse homologies and correspondence between the genetic and G-band maps and replaced the previous linkage map, to maps of man-mouse homologies, [ 12 ]  cancer-related genes, [ 13 ]  the Genetic Imprinting map ( http://mousebook.org ), the chromosome aberration map, [ 14 ] [ 15 ] [ 16 ]  and a probe/clone map.


In February 1990  Mouse News Letter  changed its name to  Mouse Genome .  In addition to the lists, maps and unrefereed contributions, short refereed papers were published. Starting in 1991  Mouse Genome  was published four times a year as one volume with four issues. As before, each issue had a theme and contained contributions and short papers. The first issue of the year was a “Maps” issue, the second issue was a “Genes“ issue, the third issue was “Inbred Strains” and the fourth issue was a DNA probes and Restriction fragment length polymorphism issue.


During the 1990s it became clear with the exponential increase in knowledge that the long-term future of mouse genetics information was an electronic one. In 1998  Mouse Genome , the official journal of the International Committee for Standardized Genetic Nomenclature for Mice, merged with  Mammalian Genome  the official journal of the  International Mammalian Genome Society . [ 17 ]  The merged journal kept the name Mammalian Genome and includes the words “Incorporating Mouse Genome” on its front cover. Information contained in the lists and maps is available from the Jackson Laboratory ( http://www.jax.org ) and MRC Harwell ( http://mousebook.org ).


Mouse News Letter continues to exist as a company Mouse News Letter Ltd, limited by guarantee and with charitable status. Its purpose is “To promote the advancement of knowledge in the science of genetics for the benefit of the public”. It receives an income from Mammalian Genome to which it sold its publishing assets. It uses this income to provide funds to enable younger scientists to attend Mouse Genetics Conferences.


For a complete archive of Mouse News Letter the MRC Harwell website see ( https://www.har.mrc.ac.uk/about-harwell/history/ )


1949 LC Dunn and Salome Gluecksohn-Waelsch,
1950-1956 Toby Carter,
1956-1970 Mary Lyon,
1970-1982 Tony Searle,
1982-1997 Jo Peters,
1986 -1997 Michael Festing for the Inbred Strains issue,
1991-1997 Steve Brown for the Maps issue


Mutation Research  is a  peer-reviewed   scientific journal  that publishes research papers in the area of  mutation   research  which focus on fundamental mechanisms underlying the  phenotypic  and  genotypic  expression of  genetic damage . There are currently three sections:


Two previous sections


are now continued as  DNA Repair .


Nature Genetics  is a  peer-reviewed   scientific journal  published by  Nature Portfolio . It was established in 1992. [ 1 ]  It covers research in  genetics . The  chief editor  is  Tiago Faial . [ 2 ]


The journal encompasses genetic and functional  genomic  studies on human traits and on other model organisms, including mouse, fly, nematode and yeast. Current emphasis is on the genetic basis for common and complex diseases and on the functional mechanism, architecture and evolution of gene networks, studied by experimental perturbation.


According to the  Journal Citation Reports , the journal has a 2023  impact factor  of 31.7, ranking it 2nd out of 175 journals in the category "Genetics & Heredity". [ 3 ]


Nature Reviews Genetics  is a monthly  review journal  published by  Nature Portfolio . It was established in 2000 and covers the full breadth of modern genetics. The  editor-in-chief  is  Linda Koch . [ 1 ]  The journal publishes  review  and perspective articles written by experts in the field subject to  peer review  and  copy editing  to provide authoritative coverage of topics. Each issue also contains Research Highlight articles – short summaries written by the editors that describe recent research papers.


According to the  Journal Citation Reports , the journal has a 2021  impact factor  of 59.943, ranking it 1st out of 175 journals in the category "Genetics & Heredity". [ 2 ]


New Genetics and Society  is a triannual  peer-reviewed   scientific journal  covering  sociological  perspectives on contemporary  genetics  and related  biological sciences . It was established in 1999 by Peter Glasner and Harry Rothman, with its first issue appearing in April of that year. [ 1 ]  It is published by  Routledge  and the  editors-in-chief  are Richard Tutton ( Lancaster University ) and Adam Hedgecoe ( University of Cardiff ). According to the  Journal Citation Reports , the journal has a 2017  impact factor  of 1.571. [ 2 ]


Oncogene  is a  peer-reviewed   scientific journal  published under the  Springer Nature  addressing cancer cell genetics and the structure and function of  oncogenes . The journal has editorial office in  London, England . The journal was established in 1987. [ 1 ]  An  open access  online-only  sister journal ,  Oncogenesis , was established in 2012 by  Douglas R. Green , who was then  Oncogene ' s  editor-in-chief . [ 2 ]


Oncogene  received a 2023  impact factor  of 6.9 and received  Journal Citation Reports  rankings of 18th out of 191 in the category  Genetics & Heredity , 29th out of 205 in the category  Cell Biology , 32nd out of 313 in the category  Biochemistry & Molecular Biology , and 43rd out of 322 journals in the category  Oncology . [ 3 ]


The current editors-in-chief are George Miller and  Justin Stebbing . [ 4 ]


The journal is abstracted and indexed in: [ 3 ]
EBSCO Discovery Service,  Summon by ProQuest, BIOSIS, Current Contents/Life Sciences, Science Citation Index Expanded, SCOPUS, EBSCO Academic Search, EBSCO Advanced Placement Source, EBSCO Agriculture Plus, EBSCO Biomedical Reference Collection, EBSCO Science & Technology Collection, EBSCO STM Source, EBSCO TOC Premier, and INIS Atomindex.


This article about an  oncology   journal  is a  stub . You can help Wikipedia by  expanding it .


Pharmacogenomics  is a  peer-reviewed   medical journal  established in 2000 and published by Future Medicine. The  editors-in-chief  are David Gurwitz ( Tel-Aviv University ), Howard McLeod ( University of North Carolina at Chapel Hill ), and Munir Pirmohamed ( University of Liverpool ). The journal covers the field of  pharmacogenomics .


The journal is abstracted and indexed in  Biological Abstracts ,  BIOSIS Previews ,  Biotechnology Citation Index ,  Chemical Abstracts ,  Current Contents /Life Sciences,  EMBASE / Excerpta Medica ,  Index Medicus / MEDLINE / PubMed ,  Science Citation Index , and  Scopus . According to the  Journal Citation Reports , the journal has a 2016  impact factor  of 2.350, ranking it 132nd out of 256 journals in the category "Pharmacology & Pharmacy". [ 1 ]


PLOS Genetics  is a  peer-reviewed   open access   scientific  journal established in 2005 and published by the  Public Library of Science . [ 1 ]  The founding  editor-in-chief  was Wayne N. Frankel ( Columbia University Medical Center ). The current editors-in-chief are Gregory S. Barsh ( HudsonAlpha Institute of Biotechnology  and  Stanford University School of Medicine ) and Gregory P. Copenhaver ( The University of North Carolina at Chapel Hill ). The journal covers research on all aspects of  genetics  and  genomics .


According to the  Journal Citation Reports , the journal has a 2020  impact factor  of 5.917. [ 10 ]


Since its tenth year of publication, the journal annually awards the $5000  PLOS Genetics Research Prize  for the best paper published in the previous year based on nominations from members of the genetics community. [ 11 ] [ 12 ]


The  Proceedings of the Natural History Society of Brünn  (German:  Verhandlungen des naturforschenden Vereines in Brünn ) was the official journal of the Natural History Society in  Brno  ( German :  Brünn ), published from 1861-1920.  A free archive of the journal is available through the  Biodiversity Heritage Library .


This was the  journal  where  Gregor Mendel  published his scientific discoveries on  genetics  which he made between 1856 and 1863. [ 1 ]


The society (German:  Naturforschenden Verein Brünn ) was organized in 1861 by Franz Czermak, Jacob Kalmus, Alexander Makowsky, Johann Nave, and Gustav von Niessl. [ 2 ]


The  Russian Journal of Genetics  is a monthly  peer-reviewed   scientific journal  covering  genetics . It was established in 1994 and is published by  Springer Science+Business Media . The  editor-in-chief  is Nikolay Yankovsky (Vavilov Institute of General Genetics). According to the  Journal Citation Reports , the journal has a 2020  impact factor  of 0.581. [ 1 ]


Somatic Cell and Molecular Genetics  was a  peer-reviewed   scientific journal  in the fields of  cell biology  and  molecular genetics .


The journal was established in 1975 as  Somatic Cell Genetics . The founding  editor-in-chief  was  Richard L. Davidson  (then of the  University of Illinois College of Medicine ). [ 1 ]  The journal expanded scope to encompass the increased development of molecular genetics and changed its name to reflect this with the tenth volume January 1984 edition. [ 2 ]  Davidson was succeeded [ when? ]  as editor-in-chief by his colleague,  Elliot R. Kaufman . [ 3 ]  The journal was published by  Springer group companies : Plenum Press until 1992, then by Kluwer until publication ceased in 2002. Publication frequency was mostly bimonthly.


Somatic Cell and Molecular Genetics  is fully indexed in  Index Medicus ,  MEDLINE , and  PubMed . [ 4 ]


Theoretical and Applied Genetics  is a  peer-reviewed   scientific journal  published by  Springer Science+Business Media . The journal publishes articles in the fields of plant  genetics ,  genomics , and  biotechnology . It was established in 1929 as  Der Züchter , which name was changed to the current one in 1968. [ 1 ]  Previous editors include  H. Stubbe  (1946–1976) and  H. F. Linskens  (1977–1987). [ 1 ]  The journal publishes only original  research articles .


Theoretical and Applied Genetics  is abstracted and indexed in Aquatic Sciences and Fisheries Abstracts,  Chemical Abstracts ,  Current Contents ,  PubMed ,  Science Citation Index , and  Scopus . [ 2 ]  According to the  Journal Citation Reports , its 2010  impact factor  is 3.264. This ranks it second out of 74 journals in the category "Agronomy", first out of 30 in "Horticulture", 23rd out of 187 in "Plant Sciences", and 59th out of 156 in "Genetics & Heredity". [ 3 ]


A  genetic chimerism  or  chimera  ( / k aɪ ˈ m ɪər ə /   ky- MEER -ə  or  / k ɪ ˈ m ɪər ə /   kim- EER -ə ) is a single organism composed of cells with more than one distinct  genotype . Animal chimeras can be produced by the fusion of two (or more)  embryos . In plants and some animal chimeras,  mosaicism  involves
distinct types of tissue that originated from the same zygote but differ due to  mutation  during ordinary  cell division .


Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage. [ 1 ]  More practically, in agronomy Chimera indicates a plant or portion of a plant whose tissues are made up of two or more types of cells with different genetic makeup; it can derive from a bud mutation or, more rarely, at the grafting point, from the concrescence of cells of the two bionts; in this case it is commonly referred to as a "graft hybrid", although it is not a hybrid in the genetic sense of "hybrid". [ 2 ]


In contrast, an individual where each cell contains genetic material from two organisms of different breeds, varieties, species or genera is called a  hybrid . [ 3 ]


Another way that chimerism can occur in animals is by  organ  transplantation, giving one individual tissues that developed from a different  genome . For example,  transplantation  of  bone marrow  often determines the recipient's ensuing  blood type . [ 4 ]


Some level of chimerism occurs naturally in the wild in many animal species, and in some cases may be a required (obligate) part of their life cycle.


Chimerism occurs naturally in adult  Ceratioid   anglerfish  and is in fact a natural and essential part of their life cycle. Once the male achieves adulthood, it begins its search for a female. Using strong  olfactory (or smell)  receptors, the male searches until it locates a female anglerfish. The male, less than an inch in length, bites into her skin and releases an enzyme that digests the skin of both his mouth and her body, fusing the pair down to the blood-vessel level. While this attachment has become necessary for the male's survival, it will eventually consume him, as both anglerfish fuse into a single  hermaphroditic  individual. Sometimes in this process, more than one male will attach to a single female as a symbiote. In this case, they will all be consumed into the body of the larger female angler. Once fused to a female, the males will reach sexual maturity, developing large  testicles  as their other organs  atrophy . This process allows for sperm to be in constant supply when the female produces an egg, so that the chimeric fish is able to have a greater number of offspring. [ 5 ]


Chimerism has been found in some species of marine sponges. [ 6 ]  Four distinct genotypes have been found in a single individual, and there is potential for even greater genetic heterogeneity. Each genotype functions independently in terms of reproduction, but the different intra-organism genotypes behave as a single large individual in terms of ecological responses like growth. [ 6 ]


It has been shown that male  yellow crazy ants  are obligate chimeras, the first known such case. In this species, the queens have arisen from fertilized eggs with a genotype of RR (Reproductive × Reproductive), the sterile female workers show a RW arrangement (Reproductive × Worker), and the males instead of being haploid, as is usually the case for ants, also display a RW genotype, but for them the egg R and the sperm W do not fuse so they develop as a chimera with some cells carrying an R and others carrying a W genome. [ 7 ] [ 8 ]


Artificial chimerism refers to examples of chimerism that are accidentally produced by humans, either for research or commercial purposes.


Tetragametic chimerism is a form of congenital chimerism. This condition occurs through fertilizing two separate ova by two sperm, followed by aggregation of the two at the  blastocyst  or zygote stages. This results in the development of an organism with intermingled cell lines. Put another way, the chimera is formed from the merging of two  nonidentical twins . As such, they can be male, female, or intersex.  [ 9 ] [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] [ 15 ] [ excessive citations ]


The tetragametic state has important implications for organ or  stem cell  transplantation. Chimeras typically have  immunologic tolerance  to both cell lines. [ citation needed ]


Microchimerism is the presence of a small number of cells that are genetically distinct from those of the host individual. Most people are born with a few cells genetically identical to their mothers' and the proportion of these cells goes down in healthy individuals as they get older. People who retain higher numbers of cells genetically identical to their mother's have been observed to have higher rates of some autoimmune diseases, presumably because the immune system is responsible for destroying these cells and a common immune defect prevents it from doing so and also causes autoimmune problems.


The higher rates of autoimmune diseases due to the presence of maternally-derived cells is why in a 2010 study of a 40-year-old man with scleroderma-like disease (an autoimmune rheumatic disease), the female cells detected in his blood stream via FISH (fluorescence in situ hybridization) were thought to be maternally-derived. However, his form of microchimerism was found to be due to a vanished twin, and it is unknown whether microchimerism from a vanished twin might predispose individuals to autoimmune diseases as well. [ 16 ]  Mothers often also have a few cells genetically identical to those of their children, and some people also have some cells genetically identical to those of their siblings (maternal siblings only, since these cells are passed to them because their mother retained them). [ citation needed ]


Germline chimerism occurs when the germ cells (for example,  sperm  and  egg  cells) of an organism are not genetically identical to its own. It has been recently discovered that  marmosets  can carry the reproductive cells of their (fraternal) twin siblings due to placental fusion during development. (Marmosets almost always give birth to fraternal twins.) [ 17 ] [ 18 ] [ 19 ]


As the organism develops, it can come to possess  organs  that have different sets of  chromosomes . For example, the chimera may have a  liver  composed of cells with one set of chromosomes and have a  kidney  composed of cells with a second set of chromosomes. This has occurred in humans, and at one time was thought to be extremely rare although more recent evidence suggests that this is not the case. [ 20 ] [ 21 ]


This is particularly true for the  marmoset . Recent research shows most marmosets are chimeras, sharing DNA with their  fraternal twins . [ 17 ]  95% of marmoset fraternal twins trade blood through  chorionic  fusions, making them  hematopoietic  chimeras. [ 22 ] [ 23 ]


In the  budgerigar , due to the many existing  plumage colour variations , tetragametic chimeras can be very conspicuous, as the resulting bird will have an obvious split between two colour types –  often divided bilaterally down the centre. These individuals are known as  half-sider budgerigars . [ 24 ]


An animal chimera is a single  organism  that is composed of two or more different populations of genetically distinct  cells  that originated from different  zygotes  involved in  sexual reproduction . If the different cells have emerged from the same zygote, the organism is called a  mosaic . Innate chimeras are formed from at least four parent cells (two fertilised eggs or early embryos fused together). Each population of cells keeps its own character and the resulting organism is a mixture of tissues. Cases of  human chimeras  have been documented. [ 20 ]


Some consider  mosaicism  to be a form of chimerism, [ 25 ]  while others consider them to be distinct. [ 26 ] [ 27 ] [ 28 ]  Mosaicism involves a  mutation  of the genetic material in a cell, giving rise to a subset of cells that are different from the rest. Natural chimerism is the fusion of more than one fertilized  zygote  in the early stages of  prenatal development . It is much rarer than mosaicism. [ 28 ]


In artificial chimerism, an individual has one  cell lineage  that was inherited genetically at the time of the formation of the human embryo and the other that was introduced through a procedure, including  organ transplantation  or  blood transfusion . [ 29 ]  Specific types of transplants that could induce this condition include bone marrow transplants and organ transplants, as the recipient's body essentially works to permanently incorporate the new blood stem cells into it.


Boklage argues that many human 'mosaic' cell lines will be "found to be chimeric if properly tested". [ 30 ]


In contrast, a human where each cell contains genetic material from two organisms of different breeds, varieties, species or genera is called a  human–animal hybrid . [ 31 ]


While German  dermatologist   Alfred Blaschko  described  Blaschko's lines  in 1901, the genetic science took until the 1930s to approach a vocabulary for the phenomenon. The term  genetic chimera  has been used at least since the 1944 article of Belgovskii. [ 32 ]


This condition is either innate or it is synthetic, acquired for example through the infusion of  allogeneic   blood cells  during  transplantation  or  transfusion . [ citation needed ]


In nonidentical twins, innate chimerism occurs by means of blood vessel  anastomoses . The likelihood of offspring being a chimera is increased if it is created via  in vitro fertilisation . [ 14 ]  Chimeras can often breed, but the fertility and type of offspring depend on which cell line gave rise to the ovaries or testes; varying degrees of  intersex  differences may result if one set of cells is genetically female and another genetically male. [ citation needed ]


On January 22, 2019, the  National Society of Genetic Counselors  released an article  Chimerism Explained: How One Person Can Unknowingly Have Two Sets of DNA , where they state, "where a twin pregnancy evolves into one child, is currently believed to be one of the rarer forms. However, we know that 20 to 30% of singleton pregnancies were originally a twin or a multiple pregnancy". [ 33 ]


Most human chimeras will go through life without realizing they are chimeras. The difference in phenotypes may be subtle (e.g., having a  hitchhiker's thumb  and a straight thumb, eyes of slightly different colors, differential hair growth on opposite sides of the body, etc.) or completely undetectable. Chimeras may also show, under a certain spectrum of UV light, distinctive marks on the back resembling that of arrow points pointing downward from the shoulders down to the lower back; this is one expression of pigment unevenness called  Blaschko's lines . [ 34 ]


Another case was that of Karen Keegan, who was also suspected (initially) of not being her children's biological mother, after DNA tests on her adult sons for a kidney transplant she needed, seemed to show she was not their mother. [ 20 ] [ 35 ]


The distinction between sectorial, mericlinal and periclinal  plant chimeras  is widely used. [ 36 ] [ 37 ]  Periclinal chimeras involve a genetic difference that persists in the descendant cells of a particular  meristem  layer. This type of chimera is more stable than mericlinal or sectoral mutations that affect only later generations of cells. [ 38 ]


These are produced by grafting genetically different parents, different  cultivars  or different species (which may belong to different genera). The tissues may be partially fused together following  grafting  to form a single growing organism that preserves both types of tissue in a single shoot. [ 39 ]  Just as the constituent species are likely to differ in a wide range of features, so the behavior of their  periclinal  chimeras is like to be highly variable. [ 40 ]  The first such known chimera was probably the  Bizzarria , which is a fusion of the  Florentine citron  and the  sour orange . Well-known examples of a graft-chimera are  Laburnocytisus  'Adamii' , caused by a fusion of a  Laburnum  and a  broom , and "Family" trees, where multiple varieties of apple or pear are grafted onto the same tree. Many fruit trees are cultivated by grafting the body of a sapling onto a  rootstock . [ 41 ]


These are chimeras in which the layers differ in their  chromosome  constitution. Occasionally, chimeras arise from loss or gain of individual chromosomes or chromosome fragments owing to  misdivision . [ 42 ]  More commonly cytochimeras have simple multiple of the normal chromosome complement in the changed layer. There are various effects on cell size and growth characteristics.


These chimeras arise by spontaneous or induced mutation of a nuclear gene to a dominant or recessive allele. As a rule, one character is affected at a time in the leaf, flower, fruit, or other parts. [ citation needed ]


These chimeras arise by spontaneous or induced mutation of a plastid gene, followed by the sorting-out of two kinds of plastid during vegetative growth. Alternatively, after selfing or  nucleic acid thermodynamics , plastids may sort-out from a mixed egg or mixed zygote respectively. This type of chimera is recognized at the time of origin by the sorting-out pattern in the leaves. After sorting-out is complete, periclinal chimeras are distinguished from similar looking nuclear gene-differential chimeras by their  non-mendelian inheritance . The majority of variegated-leaf chimeras are of this kind. [ citation needed ]


All plastid gene- and some nuclear gene-differential chimeras affect the color of the plasmids within the leaves, and these are grouped together as  chlorophyll  chimeras, or preferably as variegated leaf chimeras. For most variegation, the mutation involved is the loss of the  chloroplasts  in the mutated tissue, so that part of the plant tissue has no green pigment and no  photosynthetic  ability. This mutated tissue is unable to survive on its own, but it is kept alive by its partnership with normal photosynthetic tissue. Sometimes chimeras are also found with layers differing in respect of both their nuclear and their plastid genes. [ citation needed ]


There are multiple reasons to explain the occurrence of plant chimera during the plant recovery stage:


Untransformed cells should be easy to detect and remove to avoid chimeras. This is because it is important to maintain the stable ability of the transgenic plants across different generations. Reporter genes such as  GUS  and  Green Fluorescent Protein [ 45 ]  (GFP) are used in combination with plant selective markers (herbicide, antibody etc.). However, GUS expression depends on the plant development stage and GFP may be influenced by the green tissue autofluorescence.  Quantitative PCR  could be an alternative method for chimera detection. [ 46 ]


In 2012, the first example of a naturally-occurring RNA-DNA hybrid virus was unexpectedly discovered during a  metagenomic  study of the acidic extreme environment of  Boiling Springs Lake  that is in  Lassen Volcanic National Park , California. [ 47 ] [ 48 ]  The virus was named BSL-RDHV (Boiling Springs Lake RNA DNA Hybrid Virus). [ 49 ]  Its  genome  is related  to a DNA  circovirus , which usually infects birds and pigs, and a RNA  tombusvirus , which infect plants. The study surprised scientists, because DNA and RNA viruses vary and the way the chimera came together was not understood. [ 47 ] [ 50 ]


Other viral chimeras have also been found, and the group is known as the CHIV viruses ("chimeric viruses"). [ 51 ]


The first known primate chimeras are the rhesus monkey twins, Roku and Hex, each having six genomes. They were created by mixing cells from  totipotent  four-cell morulas; although the cells never fused, they worked together to form organs. It was discovered that one of these primates, Roku, was a sexual chimera; as four percent of Roku's blood cells contained two x chromosomes. [ 22 ]


A major milestone in chimera experimentation occurred in 1984 when a chimeric  sheep–goat  was produced by combining  embryos  from a  goat  and a  sheep , and survived to adulthood. [ 52 ]


To research the developmental biology of the bird embryo, researchers produced artificial quail-chick chimeras in 1987. By using transplantation and  ablation  in the chick embryo stage, the neural tube and the neural crest cells of the chick were ablated, and replaced with the same parts from a quail. [ 53 ]  Once hatched, the quail feathers were visibly apparent around the wing area, whereas the rest of the chick's body was made of its own chicken cells.


In August 2003, researchers at the  Shanghai Second Medical University  in China reported that they had successfully fused human skin cells and  rabbit  ova to create the first human chimeric embryos. The embryos were allowed to develop for several days in a laboratory setting, and then destroyed to harvest the resulting  stem cells . [ 54 ]  In 2007, scientists at the  University of Nevada  School of Medicine created a sheep whose blood contained 15% human cells and 85% sheep cells. [ citation needed ]


In 2023 a study reported the first chimeric monkey using embryonic stem cell lines, it was the only live birth from 12 pregnancies resulting from 40 implanted embryos of the  crab-eating macaque , an average of 67% and a highest of 92% of the cells across the 26 tested tissues were descendants of the donor stem cells against 0.1–4.5% from previous experiments on chimeric monkeys. [ 55 ] [ 56 ] [ 57 ]


Chimeric mice are important animals in biological research, as they allow for the investigation of a variety of biological questions in an animal that has two distinct genetic pools within it. These include insights into problems such as the tissue specific requirements of a gene, cell lineage, and cell potential.


The general methods for creating chimeric mice can be summarized either by injection or aggregation of embryonic cells from different origins. The first chimeric mouse was made by  Beatrice Mintz  in the 1960s through the aggregation of eight-cell-stage embryos. [ 58 ]  Injection on the other hand was pioneered by Richard Gardner and Ralph Brinster who injected cells into blastocysts to create chimeric mice with germ lines fully derived from injected  embryonic stem cells  (ES cells). [ 59 ]  Chimeras can be derived from mouse embryos that have not yet implanted in the uterus as well as from implanted embryos. ES cells from the inner cell mass of an implanted blastocyst can contribute to all cell lineages of a mouse including the germ line. ES cells are a useful tool in chimeras because genes can be mutated in them through the use of  homologous recombination , thus allowing  gene targeting . Since this discovery occurred in 1988, ES cells have become a key tool in the generation of specific chimeric mice. [ 60 ]


The ability to make mouse chimeras comes from an understanding of early mouse development. Between the stages of fertilization of the egg and the implantation of a blastocyst into the uterus, different parts of the mouse embryo retain the ability to give rise to a variety of cell lineages. Once the embryo has reached the blastocyst stage, it is composed of several parts, mainly the  trophectoderm , the  inner cell mass , and the  primitive endoderm . Each of these parts of the blastocyst gives rise to different parts of the embryo; the inner cell mass gives rise to the embryo proper, while the trophectoderm and primitive endoderm give rise to extra embryonic structures that support growth of the embryo. [ 61 ]  Two- to eight-cell-stage embryos are competent for making chimeras, since at these stages of development, the cells in the embryos are not yet committed to give rise to any particular cell lineage, and could give rise to the inner cell mass or the trophectoderm. In the case where two diploid eight-cell-stage embryos are used to make a chimera, chimerism can be later found in the  epiblast , primitive  endoderm , and trophectoderm of the mouse  blastocyst . [ 62 ] [ 63 ]


It is possible to dissect the embryo at other stages so as to accordingly give rise to one lineage of cells from an embryo selectively and not the other. For example, subsets of blastomeres can be used to give rise to chimera with specified cell lineage from one embryo. The Inner Cell Mass of a diploid blastocyst, for example, can be used to make a chimera with another blastocyst of eight-cell diploid embryo; the cells taken from the inner cell mass will give rise to the primitive endoderm and to the epiblast in the chimera mouse. [ 64 ]
From this knowledge,  ES cell  contributions to chimeras have been developed. ES cells can be used in combination with eight-cell-and two-cell-stage embryos to make chimeras and exclusively give rise to the embryo proper. Embryos that are to be used in chimeras can be further genetically altered to specifically contribute to only one part of chimera. An example is the chimera built off of ES cells and tetraploid embryos, which are artificially made by electrofusion of two two-cell diploid embryos. The tetraploid embryo will exclusively give rise to the trophectoderm and primitive endoderm in the chimera. [ 65 ] [ 66 ]


There are a variety of combinations that can give rise to a successful chimera mouse and –  according to the goal of the experiment –  an appropriate cell and embryo combination can be picked; they are generally but not limited to diploid embryo and ES cells, diploid embryo and diploid embryo, ES cell and tetraploid embryo, diploid embryo and tetraploid embryo, ES cells and ES cells. The combination of embryonic stem cell and diploid embryo is a common technique used for the making of chimeric mice, since gene targeting can be done in the embryonic stem cell. These kinds of chimeras can be made through either aggregation of stem cells and the diploid embryo or injection of the stem cells into the diploid embryo. If embryonic stem cells are to be used for gene targeting to make a chimera, the following procedure is common: a construct for homologous recombination for the gene targeted will be introduced into cultured mouse embryonic stem cells from the donor mouse, by way of electroporation; cells positive for the recombination event will have antibiotic resistance, provided by the insertion cassette used in the gene targeting; and be able to be positively selected for. [ 67 ] [ 68 ]  ES cells with the correct targeted gene are then injected into a diploid host mouse blastocyst. Then, these injected blastocysts are implanted into a pseudo pregnant female surrogate mouse, which will bring the embryos to term and give birth to a mouse whose germline is derived from the donor mouse's ES cells. [ 69 ]  This same procedure can be achieved through aggregation of ES cells and diploid embryos, diploid embryos are cultured in aggregation plates in wells where single embryos can fit, to these wells ES cells are added the aggregates are cultured until a single embryo is formed and has progressed to the blastocyst stage, and can then be transferred to the surrogate mouse. [ 70 ]


The US and Western Europe have strict codes of ethics and regulations in place that expressly forbid certain subsets of experimentation using human cells, though there is a vast difference in the regulatory framework. [ 71 ]  Through the creation of human chimeras comes the question: where does society now draw the line of humanity? This question poses serious legal and moral issues, along with creating controversy. Chimpanzees, for example, are not offered any legal standing, and are  put down  if they pose a threat to humans. If a chimpanzee is genetically altered to be more similar to a human, it may blur the ethical line between animal and human. Legal debate would be the next step in the process to determine whether certain chimeras should be granted legal rights. [ 72 ]  Along with issues regarding the rights of chimeras, individuals have expressed concern about whether or not creating human chimeras diminishes the "dignity" of being human. [ 73 ]


A  human chimera  is a  human  with a subset of cells with a distinct  genotype  than other cells, that is, having  genetic chimerism . In contrast, an individual where each cell contains genetic material from a human and an animal is called a  human–animal hybrid , while an organism that contains a mixture of human and non-human cells would be a  human-animal chimera . [ 1 ]


Some consider  mosaicism  to be a form of chimerism, [ 2 ]  while others consider them to be distinct. [ 3 ] [ 4 ] [ 5 ]


Mosaicism involves a  mutation  of the genetic material in a cell, giving rise to a subset of cells that are different from the rest.


Natural chimerism is the fusion of more than one fertilized  zygote  in the early stages of  prenatal development .  It is much rarer than mosaicism. [ 5 ]


In artificial chimerism, an individual has one  cell lineage  that was inherited genetically at the time of the formation of the human embryo and the other that was introduced through a procedure, including  organ transplantation  or  blood transfusion . [ 6 ]  Specific types of transplants that could induce this condition include bone marrow transplants and organ transplants, as the recipient's body essentially works to permanently incorporate the new blood stem cells into it.


Natural chimerism has been documented in humans in several instances.


Human-animal chimeras include humans having undergone non-human to human  xenotransplantation , which is the  transplantation  of living  cells ,  tissues  or  organs  from one  species  to another. [ 18 ] [ 19 ]


Patient derived xenografts  are created by xenotransplantation of human  tumor  cells into  immunocompromised  mice, and is a research technique frequently used in pre-clinical  oncology  research. [ 20 ]


Non-artificial chimerism has traditionally been considered to be rare due the low amount of reported cases in medical literature. [ 28 ]  However, this may be due to the fact that humans might not often be aware of this condition to begin with. There are usually no signs or symptoms for chimerism other than a few physical symptoms such as  hyper-pigmentation ,  hypo-pigmentation ,  Blaschko's lines , body asymmetry or  heterochromia iridum  (possessing two different colored eyes). [ 29 ]  However, these signs do not necessarily mean an individual is a chimera and should only be seen as possible symptoms. Again, forensic investigation or curiosity over an unexpected maternity/paternity DNA test result usually leads to the accidental discovery of this condition. By simply undergoing a DNA test, which usually consists of either a swift cheek swab or a blood test, the discovery of the once unknown second genome is made, therefore identifying that individual as a chimera. [ 30 ]


The concept of a "human hermaphrodite" resulting from chimerism is largely a misconception. [ 31 ]  Most  intersex  individuals are not chimeras, [ 32 ] [ 31 ]  and most human chimeras are not observed to have intersex traits. [ 31 ]  Theoretically, if a  gynandromorphic  human chimera were to have fully functioning male and female gonad tissue, such an individual could  self-fertilize ; [ 33 ] [ 34 ]  this hypothesis is backed by the fact that  hermaphroditic  animal species commonly reproduce in this way, and it has been observed in a rabbit. [ 35 ]   However, no such case of functional self-fertilization has ever been documented in humans; [ 36 ]  and it is non-existent or extremely rare in mammals, [ 37 ] [ 38 ] [ 39 ] [ 40 ] [ 41 ]  especially in humans. [ 42 ] [ 43 ] [ 44 ] [ 45 ]  While humans are known to have sex characteristics that diverge from typical males or typical females, these individuals fall under the  social umbrella of intersex  conditions and traits, and  some consider the term "hermaphrodite" to be a slur  when applied to them. [ 46 ] [ 47 ] [ 48 ]


On 11 July 2005, a bill known as The Human Chimera Prohibition Act was introduced into the  United States Congress  by Senator
 Samuel Brownback ; however, it died in Congress sometime in the next year. The bill was introduced based on findings that science had progressed to the point where human and nonhuman species could be merged to create new forms of life. Because of this, ethical issues might arise as the line blurred between humans and other animals, and according to the bill with this blurring of lines would come a show of disrespect for human dignity. The final claim brought up in The Human Chimera Prohibition Act was that there was an increasing amount of  zoonotic diseases , and that the creation of human-animal chimeras might allow these diseases to reach humans. [ 49 ]


On 22 August 2016, another bill, The Human-Animal Chimera Prohibition Act of 2016, was introduced to the  United States House of Representatives  by  Christopher H. Smith . It identified a human-animal chimera as:


The bill would have prohibited the attempts to create a human-animal chimera, the transfer or attempt to transfer a human embryo into a nonhuman womb, the transfer or attempt to transfer a nonhuman embryo into a human womb, and the transport or receipt of an animal chimera for any purpose. Proposed penalties for violations of this bill included fines and/or imprisonment of up to 10 years. The bill was referred to the Subcommittee on Crime, Terrorism, Homeland Security, and Investigations on October 11, 2016, but died there. [ 50 ]


In the U.S., efforts into creating a chimeric entity appeared to be legal when the topic first came up. Developmental biologist  Stuart Newman , a professor at  New York Medical College  in  Valhalla, N.Y. , applied for a patent on a human-animal chimera in 1997 as a challenge to the U.S. Patent and Trademark Office and the  U.S. Congress , motivated by his moral and scientific opposition to the notion that living things can be patented at all. Prior legal precedent had established that genetically engineered entities, in general, could be patented, even if they were based on beings occurring in nature. [ 51 ]  After a seven-year process, Newman's patent finally received a flat rejection. The legal process had created a paper trail of arguments, giving Newman what he claimed was a victory.  The Washington Post  ran an article on the controversy that stated that it had raised "profound questions about the differences—and similarities—between humans and other animals, and the limits of treating animals as property." [ 51 ]


46,XX/46,XY  is either a  chimeric  or  mosaic  genetic condition characterized by the presence of some cells that express a 46,XX  karyotype  and some cells that express a 46,XY karyotype in a single human being. [ 1 ] [ 2 ] [ 3 ]  While some individuals with this condition may be classified as  intersex , others may have typical male or female characteristics.


The cause of the condition lies in  conception or utero  with the aggregation of two distinct  zygotes  or  blastocysts  (one of which expresses 46,XX and the other of which expresses 46,XY) into a single  embryo , [ 4 ]  which subsequently leads to the development of a single individual with two distinct cell lines, instead of a pair of  fraternal twins .


In humans, sexual dimorphism is a consequence of the  XY sex-determination system . In typical prenatal  sex differentiation , the male and female embryo is anatomically identical until week 7 of the pregnancy, when the presence or the absence of the  SRY gene  on the Y chromosome causes the undetermined gonadal tissue to undergo differentiation and eventually will become either a pair of testes or ovaries respectively. [ 4 ]  The cells of the developing testes produce  Anti-Müllerian hormone , causing the regression of the  Müllerian ducts . [ 5 ]  As individuals with 46,XX/46,XY partially express the SRY gene, the normal process by which an embryo normally develops a phenotypic male or phenotypic female may be significantly affected causing variation will affect in the gonads, the reproductive tract, and the genitals. [ 6 ]  Despite this, there have been cases of completely normal sex differentiation occurring in 46,XX/46,XY individuals reported in the medical literature. [ 7 ] [ 8 ] [ 9 ]  46,XX/46,XY chimerism can be identified during pregnancy by prenatal screening or in early childhood through  genetic testing  and direct observation. [ 10 ]


The cause of this condition happens in early development resulting from a single fertilized  zygote 's cell line divided into two cell lines; a genome that contains a characterized by the presence of some cells that express a 46,XX karyotype and some cells that express a 46,XY karyotype.


46,XX/46,XY chimeric or mosaic is associated with a wide spectrum of different physical presentations, with cases ranging from having a completely normal male or female phenotype [ 7 ] [ 8 ] [ 9 ]  to some cases having  ovotesticular syndrome . Due to this variation, genetic testing is the only way to reliably make a diagnosis. [ 11 ] [ 12 ] [ 13 ] [ 6 ]


46,XX/46,XY is possible if there is direct observation of one or more of the following:


There have been no reported cases of both  gonads  being functional in the same person, the functional tissue is usually the ovarian tissue. [ 10 ]  A mix of male and female characteristics may emerge at puberty. Some individuals will experience secondary characteristics, such as breast development during puberty in a male phenotype, while others may experience deepening of the voice, secondary hair development, and gynecomastia. [ 10 ]


Segmentation of skin (distinct patches of skin) has also been observed. However, this trait is not unique to 46,XX/46,XY chimerism nor mosaicism. It has also been observed in other types of chimerism. [ 6 ]


Individuals with the condition do not experience cognitive impairment. [ 4 ]


46,XX/46,XY is an example of  tetragametic  chimerism because it requires four gametes – two sperm and two  ova .


Diagnosing a chimera or mosaic is particularly difficult due to the random distribution of 46,XX and 46,XY cells within the body. In a chimeric, an organ might be made up of a mix of 46,XX and 46,XY, but is made up entirely only one genotype. When that is the case, no abnormalities are noted and other types of tissues need to be analyzed. [ 15 ]  Blood tests might contain both or red blood cells of different blood types. [ 4 ]


Before birth, ambiguous genitalia might be observed through  ultrasound . [ 15 ]  The  karyotype  might also be observed through  amniocentesis [ 15 ]  or  cord blood  sampling.


A  chimera  or  chimeric virus  is a  virus  that contains genetic material derived from two or more distinct viruses. It is defined by the Center for Veterinary Biologics (part of the  U.S. Department of Agriculture's   Animal and Plant Health Inspection Service ) as a "new hybrid microorganism created by joining  nucleic acid  fragments from two or more different  microorganisms  in which each of at least two of the fragments contain essential  genes  necessary for replication." [ 1 ]  The term  genetic chimera  had already been defined to mean: an individual  organism  whose body contained  cell  populations from different  zygotes  or an  organism  that developed from portions of different embryos. [ citation needed ]  Chimeric  flaviviruses  have been created in an attempt to make novel live attenuated vaccines. [ 2 ]


In  mythology , a  chimera  is a creature such as a  hippogriff  or a  gryphon  formed from parts of different animals, thus the name for these viruses.


Viruses are categorized in two types: In  prokaryotes , the great majority of viruses possess double-stranded (ds)  DNA genomes , with a substantial minority of single-stranded (ss) DNA viruses and only limited presence of RNA viruses. In contrast, in  eukaryotes ,  RNA viruses  account for the majority of the  virome diversity  although ssDNA and dsDNA viruses are common as well. [ 3 ]


In 2012, the first example of a naturally-occurring RNA-DNA hybrid virus was unexpectedly discovered during a  metagenomic  study of the acidic extreme environment of  Boiling Springs Lake  that is in  Lassen Volcanic National Park , California. [ 4 ] [ 5 ]  The virus was named BSL-RDHV ( Boiling Springs Lake RNA DNA Hybrid Virus ). [ 6 ]  Its  genome  is related  to a DNA  circovirus , which usually infect birds and pigs, and a RNA  tombusvirus , which infect plants. The study surprised scientists, because DNA and RNA viruses vary and the way the chimera came together was not understood. [ 4 ] [ 7 ]


Other viral chimeras have also been found, and the group is known as the CHIV viruses ("chimeric viruses"). [ 3 ]


Combining two  pathogenic viruses  increases the lethality of the new virus [ 8 ]  which is why there have been cases where chimeric viruses have been considered for use as a  bioweapon . For example, the  Soviet Union's   Chimera Project  attempted in the late 1980s and early 1990s to combine  DNA  from  Venezuelan equine encephalitis virus  and  Smallpox virus  at one location, and  Ebola virus  and  Smallpox virus  in another location, [ 9 ] [ 10 ]  even in the face of  Boris Yeltsin 's decree of 11 April 1992.


A combination  Smallpox virus  and  Monkeypox virus  has also been studied. [ 8 ]


Studies have shown that chimeric viruses can also be developed to have medical benefits. The US  Food and Drug Administration  (FDA) has recently approved the use of  chimeric antigen receptor  (CAR) to treat relapsed  non-Hodgkin Lymphoma . By introducing a chimeric antigen receptor into  T cells , the T cells become more efficient at identifying and attacking the  tumor  cells. [ 11 ]  Studies are also in progress to create a chimeric vaccine against four types of  Dengue virus , however this has not been successful yet. [ 12 ]


Lydia Fairchild  (born 1976) is an American woman who exhibits  chimerism , having two distinct populations of DNA among the cells of her body.  She was pregnant with her third child when she and the father of her children, Jamie Townsend, separated. When Fairchild applied for enforcement of child support in 2002, providing  DNA evidence  of Townsend's paternity was a routine requirement. While the results showed Townsend to certainly be their father, they seemed to rule out her being their mother.


Fairchild stood accused of fraud by either claiming benefits for other people's children, or taking part in a  surrogacy  scam, and records of her prior births were put similarly in doubt. Prosecutors called for her two children to be taken away from her, believing them not to be hers. As time came for her to give birth to her third child, the judge ordered that an observer be present at the birth, ensure that blood samples were immediately taken from both the child and Fairchild, and be available to testify. Two weeks later, DNA tests seemed to indicate that she was also not the mother of that child.


A breakthrough came when her defense attorney, [ 1 ]  Alan Tindell, learned of  Karen Keegan , a  chimeric  woman in Boston, and suggested a similar possibility for Fairchild and then introduced an article in the  New England Journal of Medicine  about Keegan. [ 2 ] [ 3 ]  He realized that Fairchild's case might also be caused by  chimerism . As in Keegan's case, DNA samples were taken from members of the extended family. The DNA of Fairchild's children matched that of Fairchild's mother to the extent expected of a grandmother. They also found that, although the DNA in Fairchild's skin and hair did not match her children's, the DNA from a  cervical smear  test did match. Fairchild was carrying two different sets of DNA, the defining characteristic of chimerism.


This United States biographical article is a  stub . You can help Wikipedia by  expanding it .


Grafting  or  graftage [ 1 ]  is a  horticultural  technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion ( / ˈ s aɪ ə n / ) while the lower part is called the rootstock. The success of this joining requires that the vascular tissues grow together. The natural equivalent of this process is  inosculation . The technique is most commonly used in  asexual   propagation  of commercially grown plants for the  horticultural  and  agricultural  trades. The scion is typically joined to the rootstock at the soil line; however, top work grafting may occur far above this line, leaving an understock consisting of the lower part of the trunk and the root system.


In most cases, the  stock  or  rootstock  is selected for its  roots  and the  scion  is selected for its  stems ,  leaves ,  flowers , or  fruits . [ 1 ]  The scion contains the desired  genes  to be duplicated in future production by the grafted plant.


In stem grafting, a common grafting method, a  shoot  of a selected, desired plant  cultivar  is grafted onto the stock of another type. In another common form called bud grafting, a dormant side bud is grafted onto the stem of another stock plant, and when it has inosculated successfully, it is encouraged to grow by  pruning  off the stem of the stock plant just above the newly grafted bud.


For successful grafting to take place, the  vascular cambium  tissues of the stock and scion plants must be placed in contact with each other. Both tissues must be kept alive until the graft has "taken", usually a period of a few  weeks . Successful grafting only requires that a vascular connection take place between the grafted tissues. Research conducted in  Arabidopsis thaliana   hypocotyls  has shown that the connection of  phloem  takes place after three days of initial grafting, whereas the connection of  xylem  can take up to seven days. [ 2 ]  Joints formed by grafting are not as strong as naturally formed joints, so a physical weak point often still occurs at the graft because only the newly formed tissues inosculate with each other. The existing structural tissue (or wood) of the stock plant does not fuse.


Precocity : The ability to induce fruitfulness without the need for completing the juvenile phase. Juvenility is the natural state through which a seedling plant must pass before it can become reproductive. In most fruiting trees, juvenility may last between 5 and 9 years, but in some tropical fruits, e.g.,  mangosteen , juvenility may be prolonged for up to 15 years. Grafting of mature  scions  onto rootstocks can result in fruiting in as little as two years.


Dwarfing : To induce dwarfing or cold tolerance or other characteristics to the scion. Most  apple  trees in modern  orchards  are grafted on to dwarf or semi-dwarf trees planted at high density. They provide more  fruit  per unit of land, of higher quality, and reduce the danger of accidents by harvest crews working on ladders. Care must be taken when planting dwarf or semi-dwarf trees. If such a tree is planted with the graft below the soil, then the scion portion can also grow roots and the tree will still grow to its standard size.


Ease of propagation : Because the scion is difficult to propagate vegetatively by other means, such as by  cuttings . In this case, cuttings of an easily rooted plant are used to provide a rootstock. In some cases, the scion may be easily propagated, but grafting may still be used because it is commercially the most cost-effective way of raising a particular type of plant.


Hybrid breeding : To speed maturity of  hybrids  in fruit tree breeding programs. Hybrid seedlings may take ten or more years to  flower  and fruit on their own roots. Grafting can reduce the time to flowering and shorten the breeding program.


Hardiness : Because the scion has weak roots or the roots of the stock plants are tolerant of difficult conditions. e.g. many  Western Australian  plants are sensitive to  dieback  on heavy soils, common in urban gardens, and are grafted onto hardier  eastern Australian  relatives.  Grevilleas  and  eucalypts  are examples.


Sturdiness : To provide a strong, tall  trunk  for certain  ornamental  shrubs and trees. In these cases, a graft is made at a desired height on a stock plant with a strong stem. This is used to raise 'standard'  roses , which are rose bushes on a high stem, and it is also used for some ornamental trees, such as certain weeping cherries.


Disease/pest resistance : In areas where soil-borne pests or pathogens would prevent the successful planting of the desired cultivar, the use of pest/disease tolerant rootstocks allow the production from the cultivar that would be otherwise unsuccessful. A major example is the use of rootstocks in combating  Phylloxera .


Pollen source : To provide  pollenizers . For example, in tightly planted or badly planned apple  orchards  of a single variety, limbs of  crab apple  may be grafted at regularly spaced intervals onto trees down rows, say every fourth tree. This takes care of  pollen  needs at blossom time.


Repair : To repair damage to the trunk of a tree that would prohibit nutrient flow, such as stripping of the  bark  by  rodents  that completely girdles the trunk. In this case a  bridge graft  may be used to connect tissues receiving flow from the roots to tissues above the damage that have been severed from the flow. Where a  water sprout ,  basal shoot  or  sapling  of the same species is growing nearby, any of these can be grafted to the area above the damage by a method called inarch grafting. These alternatives to scions must be of the correct length to span the gap of the wound.


Changing cultivars : To change the  cultivar  in a fruit orchard to a more profitable cultivar, called  top working . It may be faster to graft a new cultivar onto existing limbs of established trees than to replant an entire orchard.


Genetic consistency :  Apples are notorious for their genetic variability, even differing in multiple characteristics, such as, size, color, and flavor, of fruits located on the same tree. In the commercial farming industry, consistency is maintained by grafting a scion with desired fruit traits onto a hardy stock.


Curiosities:


Compatibility of scion and stock : Because grafting involves the joining of vascular tissues between the scion and rootstock, plants lacking vascular cambium, such as  monocots , cannot normally be grafted.  As a general rule, the closer two plants are genetically, the more likely the graft union will form. Genetically identical clones and intra-species plants have a high success rate for grafting. Grafting between species of the same genus is sometimes successful. Grafting has a low success rate when performed with plants in the same family but in different genera, and grafting between different families is rare. [ 3 ]


Cambium alignment and pressure : The vascular cambium of the scion and stock should be tightly pressed together and oriented in the direction of normal growth. Proper alignment and pressure encourages the tissues to join quickly, allowing nutrients and water to transfer from the stockroot to the scion. [ 4 ] : 466


Completed during appropriate stage of plant : The grafting is completed at a time when the scion and stock are capable of producing  callus  and other wound-response tissues. Generally, grafting is performed when the scion is dormant, as premature budding can drain the grafting site of moisture before the grafting union is properly established. Temperature greatly affects the physiological stage of plants. If the temperature is too warm, premature budding may result. Elsewise, high temperatures can slow or halt callus formation. [ 3 ]


Proper care of graft site : After grafting, it is important to nurse the grafted plant back to health for a period of time. Various grafting tapes and waxes are used to protect the scion and stock from excessive water loss. Furthermore, depending on the type of graft, twine or string is used to add structural support to the grafting site. Sometimes it is necessary to prune the site, as the rootstock may produce  shoots  that inhibit the growth of the scion. [ 3 ]


Cutting tools : It is a good procedure to keep the cutting tool sharp to minimize tissue damage and clean from dirt and other substances to avoid the spread of disease. A good knife for general grafting should have a blade and handle length of about 3 inches and 4 inches respectively. Specialized knives for grafting include bud-grafting knives, surgical knives, and pruning knives.  Cleavers, chisels, and saws are utilized when the stock is too large to be cut otherwise.


Disinfecting tools : Treating the cutting tools with disinfectants ensures the grafting site is clear of  pathogens . The most commonly used sterilizing agent is  alcohol .


Graft seals : Keeps the grafting site hydrated. Good seals should be tight enough to retain moisture while, at the same time, loose enough to accommodate plant growth. Includes specialized types of clay, wax, petroleum jelly, and adhesive tape.


Tying and support materials : Adds support and pressure to the grafting site to hold the stock and scion together before the tissues join, which is especially important in herbaceous grafting. The employed material is often dampened before use to help protect the site from desiccation. Support equipment includes strips made from various substances, twine, nails, and splints. [ 5 ]


Grafting machines : Because grafting can take a lot of time and skill, grafting machines have been created. Automation is particularly popular for  seedling  grafting in countries such as Japan and Korea where farming land is both limited and used intensively. Certain machines can graft 800 seedlings /hr. [ 4 ] : 496


Approach grafting or inarching is used to join together plants that are otherwise difficult to join. The plants are grown close together, and then joined so that each plant has  roots  below and growth above the point of union. [ 6 ]  Both scion and stock retain their respective parents that may or may not be removed after joining. Also used in  pleaching . The graft can be successfully accomplished any time of year. [ 7 ]


Bud grafting (also called  chip budding  or  shield budding ) uses a bud instead of a twig. [ 8 ]  Grafting roses is the most common example of bud grafting. In this method a bud is removed from the parent plant, and the base of the bud is inserted beneath the bark of the stem of the stock plant from which the rest of the shoot has been cut. Any extra bud that starts growing  from the stem of the stock plant is removed. Examples: roses and fruit trees like peaches.


Budwood  is a stick with several buds on it that can be cut out and used for bud grafting. It is a common method of propagation for citrus trees. [ 9 ] [ 10 ] [ 11 ]


In cleft grafting a small cut is made in the stock and then the pointed end of the scion is inserted in the stock. This is best done in the early spring and is useful for joining a thin scion about  1 cm ( 3 ⁄ 8  in) diameter to a thicker branch or stock. It is best if the former has 3–5 buds and the latter is  2–7 cm ( 3 ⁄ 4 – 2 + 3 ⁄ 4  in) in diameter. The branch or stock should be split carefully down the middle to form a cleft about  3 cm ( 1 + 1 ⁄ 8  in) deep. If it is a branch that is not vertical then the cleft should be cut horizontally. The end of the scion should be cut cleanly to a long shallow wedge, preferably with a single cut for each wedge surface, and not whittled. A third cut may be made across the end of the wedge to make it straight across.


Slide the wedge into the cleft so that it is at the edge of the stock and the centre of the wedge faces are against the cambium layer between the bark and the wood. It is preferable if a second scion is inserted in a similar way into the other side of the cleft. This helps to seal off the cleft. Tape around the top of the stock to hold the scion in place and cover with grafting wax or sealing compound. This stops the cambium layers from drying out and also prevents the ingress of water into the cleft.


In whip grafting the scion and the stock are cut slanting and then joined. The grafted point is then bound with tape and covered with a soft sealant to prevent dehydration and infection by germs.  The common variation is a whip and tongue graft, which is considered the most difficult to master but has the highest rate of success as it offers the most cambium contact between the scion and the stock. It is the most common graft used in preparing commercial fruit trees. It is generally used with stock less than  1.25 cm ( 1 ⁄ 2  in) diameter, with the ideal diameter closer to  1 cm ( 3 ⁄ 8  in) and the scion should be of roughly the same diameter as the stock.


The stock is cut through on one side only at a shallow angle with a sharp knife. (If the stock is a branch and not the main trunk of the rootstock then the cut surface should face outward from the centre of the tree.) The scion is similarly sliced through at an equal angle starting just below a bud, so that the bud is at the top of the cut and on the other side than the cut face.


In the whip and tongue variation, a notch is cut downwards into the sliced face of the stock and a similar cut upwards into the face of the scion cut. These act as the tongues and it requires some skill to make the cuts so that the scion and the stock marry up neatly. The elongated "Z" shape adds strength, removing the need for a companion rod in the first season (see illustration).


The joint is then taped around and treated with tree-sealing compound or grafting wax. A whip graft without a tongue is less stable and may need added support.


Stub grafting is a technique that requires less stock than cleft grafting, and retains the shape of a tree. Also scions are generally of 6–8 buds in this process.


An incision is made into the branch  1 cm ( 3 ⁄ 8  in) long, then the scion is wedged and forced into the branch. The scion should be at an angle of at most 35° to the parent tree so that the crotch remains strong. The graft is covered with grafting compound.


After the graft has taken, the branch is removed and treated a few centimeters above the graft, to be fully removed when the graft is strong.


The four-flap graft (also called banana graft) is commonly used for pecans, and first became popular with this species in Oklahoma in 1975. [ 12 ]  It is heralded for maximum cambium overlap, but is a complex graft. It requires similarly sized diameters for the rootstock and scion. The bark of the rootstock is sliced and peeled back in four flaps, and the hardwood is removed, looking somewhat like a peeled banana. It is a difficult graft to learn.


Awl grafting takes the least resources and the least time. It is best done by an experienced grafter, as it is possible to accidentally drive the tool too far into the stock, reducing the scion's chance of survival. Awl grafting can be done by using a screwdriver to make a slit in the bark, not penetrating the cambium layer completely. Then inset the wedged scion into the incision.


Veneer grafting, or inlay grafting, is a method used for stock larger than 2.5 centimetres (1 in) in diameter. [ 13 ]  The scion is recommended to be about as thick as a pencil. Clefts are made of the same size as the scion on the side of the branch, not on top. The scion end is shaped as a wedge, inserted, and wrapped with tape to the scaffolding branches to give it more strength.


Rind grafting involves grafting a small scion onto the end of a thick stock. The thick stock is sawn off, and a ~4 cm long bark-deep cut is made parallel to the stock, from the sawn-off end down, and the bark is separated from the wood on one or both sides. The scion is shaped as a wedge, exposing cambium on both sides, and is pushed in under the back of the stock, with a flat side against the wood.


Tree  branches  and more often  roots  of the same species will sometimes naturally graft; this is called  inosculation . The bark of the tree may be stripped away when the roots make physical contact with each other, exposing the vascular cambium and allowing the roots to graft together. A group of trees can share water and mineral nutrients via root grafts, which may be advantageous to weaker trees, and may also form a larger rootmass as an adaptation to promote fire resistance and regeneration as exemplified by the California black oak ( Quercus kelloggii ). [ 14 ]  Additionally, grafting may protect the group from wind damages as a result of the increased mechanical stability provided by the grafting. [ 15 ]   Albino redwoods  use root grafting as a form of  plant parasitism  of normal redwoods.