down syndrome, how does down syndrome affect babies? i.e biological genes.
130383
Dit is nie duidelik wat jou vraag is nie.
339440
skin color will depands on who's genes is stronger..if the chinese ones, i say the baby quite fair..not as fair as 100% chienese but close like 85%..
554039
Finding out the function of each gene is a complex procedure. But once a gene is identified and singled out, silencing it by means of RNA interference is a great way to find out how it works, yes.\n\nI just wanted to add some comments.\nThere is some confusion with respect to what knowing the entire genome can and cannot do. \nA gene is defined as a portion of DNA that codes for a protein.\nHowever, differences during the translation from DNA to protein can result in different proteins with quite different properties. In the past, when genes were first discovered and studied, it was believed that each gene coded for a protein, and each protein determined a character. Many people still believe that there is a "blue eye gene" or a "intelligence gene". This is not so. \nWith some exceptions, each character that we perceive as such (for instance, curly hair, large flowers) is the result of the interaction of several alleles (the "versions" of each gene that we carry), as well as other processes and phenomena that occur between the translation of a protein and the full development of a living being (called epigenetic factors). \n\nThat being said, RNA interference is a great tool to learn more about the effects of specific genes, yes. Hopefully people will understand that in the case of complex systems such as living beings, and humans specifically, the separate study of each part is not enough to understand the whole.
337567
Only if a genetically recessive trait runs in the family and both the guy and his sister have the defective chromosome, only then does the baby risk having a birth defect or mental retardation - even then(ie, with the defective recessive chromosome in both), the chance would be 1 abnormal child out of 4. If the guy and the sister have no such defective chromosomes, then the question of an abnormal/retarded child does not arise.\n\nIf, however, a genetically dominant trait runs in the family and either the guy or his sister have the defective chromosome, then the risk increases to 1 in 2  and if both have it, then the risk is 3 out of 4.\n\nIn any case, whether the baby will be normal or abnormal cannot be determined until a karyotyping of both the guy and his sis is done. Having said that, the rate of such disorders is quite low and in all probability, the child will be normal.
149505
Different disorders.  My sister is mentally chalenged and i have found that the the kids that are worse, usually look a little different.  This can be caused by many different problems in birth.  Others are the result of down syndrome.  It is the same as a mentally stable person that doesn't look "normal".
321081
There are widespread effects from FAS. The biggest problems are with the brain, and many children with FAS have mental retardation. Other body parts affected may include the heart, face, skeleton, and genitourinary tract. There is often a distinct appearance of children with FAS, though it is not 100% consistent.
255119
Not a stupid question at all. Mutation (as mentioned above) does occur, though of course it will only affect individual cells and their descendents, not all cells in the individual. There is also a process that is being increasingly studied called genomic imprinting or epigenetic inheritance. These are not DNA sequence changes, like you asked about, but seem to be related to your question. The wikipedia article is a decent introduction but there are other summaries available.
301951
What Causes Down Syndrome   \n \n\n\nDown syndrome is usually caused by an error in cell division called non-disjunction. However, two other types of chromosomal abnormalities, mosaicism and translocation, are also implicated in Down syndrome - although to a much lesser extent. Regardless of the type of Down syndrome which a person may have, all people with Down syndrome have an extra, critical portion of the number 21 chromosome present in all, or some, of their cells. This additional genetic material alters the course of development and causes the characteristics associated with the syndrome.\n\n\nNondisjunction\n\nNondisjunction is a faulty cell division which results in an embryo with three number 21 chromosomes instead of two. Prior to, or at, conception, a pair of number 21 chromosomes, in either the sperm or the egg, fail to separate. As the embryo develops, the extra chromosome is replicated in every cell of the body. This faulty cell division is responsible for 95 percent of all cases of Down syndrome. \n\nWhy nondisjunction occurs is currently unknown, although it does seem to be related to advancing maternal age. Many people are surprised to find out that 80 percent of children born with Down syndrome are born to women under 35 years of age. This is because younger women have higher fertility rates. It does not contradict the fact that the incidence of births of children with Down syndrome increases with the age of the mother.\n\nAlthough nondisjunction can be of paternal origin, this occurs less frequently. Because this error in cell division is often present in the egg prior to conception, and women are born with their complete store of eggs, it has been postulated that some environmental factors may be implicated in nondisjunction. However, despite years of research, the cause (or causes) of nondisjunction, is still unknown. There seems to be no connection between any type of Down syndrome and parents' activities before or during pregnancy.\n\n\nMosaicism\n\nMosaicism occurs when nondisjunction of the 21st chromosome takes place in one of the initial cell divisions after fertilization. When this occurs, there is a mixture of two types of cells, some containing 46 chromosomes and some containing 47. Those cells with 47 chromosomes contain an extra 21st chromosome. Because of the "mosaic" pattern of the cells, the term mosaicism is used. Mosaicism is rare, being responsible for only one to two percent of all cases of Down syndrome.\n\nSome research has shown that individuals with mosaic Down syndrome are less affected than those with trisomy 21; however, broad generalizations are not possible due to the wide range of abilities that people with Down syndrome possess. \n\n\nTranslocation\n\nTranslocation is a different type of chromosomal problem and occurs in only three to four percent of people with Down syndrome. Translocation occurs when part of the number 21 chromosome breaks off during cell division and attaches to another chromosome. While the total number of chromosomes in the cells remains 46, the presence of an extra part of the number 21 chromosome causes the features of Down syndrome. As with nondisjunction trisomy 21, translocation occurs either prior to or at conception.\n\nUnlike nondisjunction, maternal age is not linked to the risk of translocation. Most cases are sporadic, chance events. However, in about one-third of cases, one parent is a carrier of a translocated chromosome. For this reason, the risk of recurrence for translocation is higher than that of nondisjunction. Genetic counseling can be sought to determine the origin of the translocation.
371928
Go back to before the child is concieved.  Back to the creation of these specific gametes.\n\nIn the meiosis process that created the gametes, one of the gametes that eventually combined to create the person ended up having an extra chromosome.\n\nInstead of the spindle fibres pulling the chromosomes apart perfectly in half ( "n" to each pole), one side of the cell got "n-1" and one got "n+1".  The gamete with "n-1" probably died from too little information, but the one with "n+1" ended up combining into the zygote and eventually became the coding for the person with Down's syndrome.\n\nDown's syndrome has an entire extra 21 chromosome.
504595
the first 22 are considered autosomal genes these are genes that are going to be expressed as your phenotype! The 23rd gene is your sex gene. Here (in a normal male and female) you would either have XY(male) or XX (female).
16918
There's a good article about Lupus at http://www.hopkins-arthritis.som.jhmi.edu/other/lupus.html\n\n"The good news is that only two out of 100 children whose mother has lupus will get lupus. The genetic risk is small. It is not strictly a genetic disease."\n\nHope this helps.
488790
a. Selective gene expression.\nAll diploid cells in an organism have the same genome. Specific genes are turned on or off by environmental conditions, such as hormone levels, chemicals introduced, the action and metabolites of surrounding cells. A stem cell will differentiate into a specific cell based on specific conditions. \nRemember that a human baby with many different cells is made from on cell, the fertilized egg.
153808
Actually, if two people produce a child with Cystic Fibrosis then they are both carriers of the gene. That means that everytime they reproduce there is a 1 in 4 chance that their offspring will have Cystic Fibrosis. \n\nBasically, it is a genetic matrix. Each parent donates 2 genes to the process. Each parent has one healthy gene and one CF gene. There are four possible genetic combinations when two people with the Cystic Fibrosis gene have a child. \n\nThe child could get one healthy gene from each parent and the child will not develop Cystic Fibrosis. \n\nThe child could receive one healthy gene from his mother and one CF gene from his father and the child will not develop Cystic Fibrosis. \n\nThe child could receive one healthy gene from his father and one CF gene from his mother and the child will not develop Cystic Fibrosis. \n\nThe child could get one CF gene from each parent and the child will develop Cystic Fibrosis. \n\nThere are two important things to remember.\n\nFirst, if the child receives a CF gene from his parents he has the potential of passing that gene on to his children. This is especially true if he were to have a child with a woman who also carries the gene.\n\nSecond, this does not mean that if a couple were to have four children only one would be at risk of having Cystic Fibrosis. The odds start all over with each pregnancy. It's like having a little sack with 3 red marbles and 1 blue marble in it. If you take a marble from the sack and it is red but place the marble back in before you draw again, you have an equal chance of pulling that red marble the second time (just like the first time).
198114
Statistics\n\n* Down syndrome occurs in roughly 1 of every 750 births in the United States.\n* The risk of having a child with Down syndrome is less than 1 in 2,500 among young women.\n* This risk increases to roughly 1 in 350 when women reach 35 years of age.\n* After age 45, the risk of having a child with Down Syndrome is about 1 in 25.
635010
This is like asking Why are there so many different kinds of flowers, there is no one answer for this question. Sometimes the mother makes poor or uneducated choices during pregnancy or isn't aware of being pregnant; poor neutrition, smoking, drugs, exposure to certain drugs and chemicals will negatively affect the developing baby. Generally in this situation there is damage to the tissues of the developing baby stopping things from proceeding normally.  \n\nSometimes, genetics affect the embreo in the same way identical twins develop. Genetics are the "roadmap" that tells the cells what to be and where to go. Sometimes genetics tells the egg to seperate making two identical babys, but sometimes there are flaws in the "roadmap"   and things don't develop or don't develop properly.  \n\nSometimes there is no reason at all for the disability. It's a sad start to life but good parents will help the child to make the most of their situatin and lead a productive life.
209513
In adoption studies, psychologists studied how much children's IQ was related to their parents. For example, was the biological child's IQ closer to their parent than the adopted child to their new parent? They found that biological children have a closer IQ to their biological parents than do adopted children to their new parent. So that means that nature must have played more of an important role than nurture. However, when the adopted child came from an impoverished environment and was put in a better home with better parents, their IQ increased dramatically, which means that nurture still plays a great role in influencing a child's IQ.\n\nThe types of twins are fraternal or identical.\n\nThe nature vs. Nurture debate is about whether you become the person you are because of (nature) biological factors (meaning you are born with a certain IQ and certain characteristics that you inherited from your parents and cannot change) or because of (nurture) environmental factors such as how your parents raised you, if you were in an abusive or good home, etc.
89031
Scientists have reported that they've found an "extremely unusual" trait in the cells of some mothers with two or more gay sons, providing more evidence to suggest that homosexuality might be inherited.\n\n\nMothers of multiple gay sons were about six times more likely than other women to process their X chromosomes in a certain way, researchers discovered.\n\n\nResearchers aren't entirely sure what the findings mean, said study co-author Sven Bocklandt, a postdoctoral researcher at UCLA. Making things more complicated, about 75 percent of mothers of multiple gay sons don't have the trait.\n\n\nStill, the study, released Tuesday in the journal Human Genetics, raises plenty of questions, Bocklandt said, especially as researchers try to figure out whether homosexuality has genetic roots and if there truly is a "gay gene" -- or genes.\n\n\n"What everybody wants is the gene, and we don’t have it yet," Bocklandt said. "But this is an independent confirmation that the X chromosome is involved."\n\n\nBocklandt and colleagues looked at a phenomenon known as X-chromosome inactivation, in which cells inside the bodies of females automatically turn off -- or inactivate -- one of their two X chromosomes. That leaves them with one working X chromosome -- just like males, who have a single X and a single Y chromosome.\n\n\nNormally, each cell in a female's body randomly turns off one or the other X chromosome. In some cases, such as when families share a genetic disease, there is "extreme skewing" -- one X chromosome is more likely to be turned off than the other, Bocklandt said.\n\n\nIn the new study, the researchers looked at 97 mothers of one or more gay sons and 103 women with no gay sons to see what their blood cells did with their X chromosomes. The researchers recruited many of the women with the help of PFLAG.\n\n\nThey found that nearly a quarter of the mothers of multiple gay sons inactivated the same X chromosome -- in other words, nonrandomly -- compared to just 4 percent of the women without gay sons. Of those with one gay son, 13 percent inactivated the same X chromosome.\n\n\nDr. Ionel Sandovici, a genetics researcher at the Babraham Institute in Cambridge, England, who is familiar with the research findings, cautioned that the study is small, with just 44 mothers of multiple gay sons being examined. More research in larger groups must be done to confirm the results, Sandovici said.\n\n\nThe research does provide "circumstantial evidence" that the X chromosome contributes to the development of male sexuality, Sandovici said. But "we still understand very little about molecular mechanisms of sexual orientation, and this seems to be rather a complicated biological puzzle."\n\nBut of course its Nature vs. Nurture and its possible that the person could just become gay because of his environment/experiences or just be born that way.