Is it possible to observe diffrences between heterozygous and homozygous indiv. possesing the dominant allele?
118008
No. B'coz if a perosn is heterozygous for a trait, the person will express the dominant trait. And, so will a person homozygous (dominant allele) for that trait. Therefore, it's not possible to differentiate between the two unless one obtains their karyotype chart.
594586
Well, I tend to agree with the other post on this...I wouldn't call a gene "superior" because it's dominant or recessive.  (Red hair, is, by the way, recessive!  I'm a redhead!)  A dominant allele need only be present for the trait to be apparent, that is, it can carry a recessive gene, but will show the traits of the dominant gene.  However, even though a trait is dominant, does not mean that it is the most common.  Take blood type, for example.  The O blood type is completely recessive, yet it is the most common, so I wouldn't really say that either of them are "superior".
775856
A)\n\nAs far as pod size, at least one parent must be homozygous for H, since all the offspring have one pod.  The other parent coudl have any genotype for that gene\n\nThe leaf shape is showing the 3:1 ratio characteristic of a dihybrind cross.  So both parents must be het at the leaf locus.\n\nB) is similar, since all the offspring have 3 pods, the parents must be homozygous for that recessive allele.  The other parent coudl have any genotype for that gene.\n\nThe 3:1 ratio of leaf shape shows that the parents must again both be het for the leaf shape locus.\n\nC)  If all the offspring show the dominant pheontype, one parent must be homozygous for the pod number, and one must be homozygous for the leaf shape.  Either the same parent is homozygous for both, or each is homozygous for one trait.  Again, if one parent is homozygous for a gene, the other parent coudl have any genotype at that locus.\n\nD)  The ratio of one-pod/3-pod is again, 3:1, so both parents must be het for that gene.  Since half the offspring have the dominant leaf shape, and half have the recessive leaf shape, that means that one parent must be homozygous for the recessive allel, and the other must be het.\n\ne) The ratio of one-pod/3-pod is closest to 3:1, so both parents must be het for that gene.  again, the ration is leaf shapes is closest to 1:1, so one parent must be homozygous recessive, the other het.\n\nBut the ratios aren't quite right, there's something non-Mendelian affecting the offspring here.
252610
Yes, it is dominant. People are unclear here on the difference between dominance and frequency. Because something is dominant does not mean that it occurs frequently in the population. Many disease traits are dominant but rare. How often you see a phenotype depends on how often the allele for that trait occurs in the population. Whether the allele is dominant or recessive determines whether the phenotype will manifest in the heterozygous state.
707484
A)\n\nThe white mouse shares the phenotype and genotype of parents\n\nMother white mouse: aa\nFather white mouse: aa\nWhite mouse: aa\n\nThe Brown mouse might be 2 things, \neither heterozygous: Aa\nor homozygous dominant: AA\n\n(in these type of exercises, when you mate something with an animal from which you have no info, he's usually homozygous. And if he wasn't the next step would not work.)\n\nTherefore, the mating of the white mouse (aa) with the brown mouse (AA) give only heterozygous (Aa) brown mice.\n\nWhy not B?\nBecause if the white mouse was heterozygous (Bb), that meant that "White" was the dominant gene, and the brown mouse had to be homozygous recessive (bb). But now you can say that they still could have a brown mice offspring, because they both carry a recessive allele (bb). Well, yes, but eventually white mice would appear in the be born (BB, Bb). This way it would never be all brown.\n\nWhy not C?\nBecause all the offspring would then be all white and never brown. It's the inverse of example A).\n\nWhy not D?\nBecause the white mouse is alive and fertile.
97181
half \nedit read question wrong it 2/3 of black will be heter\n\nOkay the question is What fraction of the BLACK f2 is expected to be heter And since 1/4 is Homozygous Black and 1/2 are heterzygous black.. so 2/3 Of the BlACK f2 will be heterzygous.
784007
I don't think they can be on the same chromosome. Epistatic alleles are alleles that assort independently, but can affect the function of another allele. It could be genotypic (one allele preventing transcription of another) or phenotypic (both alleles are transcribed, but one hides the effect of the other). If they are on the same chromosome, they wouldn't always sort independently; there'd be a high degree of linkage (like blond hair and blue eyes).
761641
Ss and Ss\n\nGenotype of both parents are heterozygous. If you draw out the Punnet square, you see 1/4 of the offspring will have long hair while 3/4 will have short hair. The phenotypic ratio of long hair to short hair ends up being 1:3, just like the puppies are 2:6.\n\nGenotype ratio ends up being:\n1/2 heterozygous Ss\n1/4 homozygous dominant SS\n1/4 homozygous recessive ss\n\nHope this helps.
373156
according to genetics,if both parents are homozygous black(both of each parent's alleles or genotypes are the same),the odds are ALWAYS zero.eg:both parents' genotype is BB(B-black colour is the dominant while b-white colour is recessive)the children are ALL BB,so they are All black. \n\nif one parent is heterozygous(genotypes are different),same as above.eg:if the mother is BB & the father is Bb, 2 children are BB while the other 2 are Bb,which means All are black\n\n  if both parents are heterozygous the odds are i in every 4 children. eg:both parents are Bb, 1 child is BB-black , 2 children are Bb-black & 1 child is bb-white.\n\ni hope u have studied genetics in bio-if not,then ur lost!good luck!!!
632744
B- brown (dominant), b- blue (recessive)\n\nChildren's phenotypes: both blue\nChildren's genotypes: both bb\n\nParents phenotypes: both brown\nSo, both parent must be heterozygous for eye colour:\nParents genotypes: both Bb
490031
Ok, here's how it works. It seems that you need genotypes. A homozygous trait is a trait that is both dominant and recessive. Therefore, the organism possesses the dominant trait. A heterozygous genotype is always dominant (dominant is dominant over recessive). For example, brown hair (B) is dominant over blond hair (b). a heterozygous person will be Hh, and will have brown hair even though both alleles are present.
241930
Mendel's law of dominance\nIn a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation. Offspring that are hybrid for a trait will have only the dominant trait in the phenotype. \n[edit]\nMendel's law of segregation\n \nFigure 3 : The color alleles of Mirabilis jalapa are not dominant or recessive.\n(1) Parental generation. (2) F1 generation. (3) F2 generation. The "red" and "white" allele together make a "pink" phenotype, resulting in a 1:2:1 ratio of red:pink:white in the F2 generation. \nFigure 1 : Dominant and recessive phenotypes.\n(1) Parental generation. (2) F1 generation. (3) F2 generation. Dominant (red) and recessive (white) phenotype look alike in the F1 (first) generation and show a 3:1 ratio in the F2 (second) generationMendel's law of segregation, also known as Mendel's first law, essentially has four parts.\n\nAlternative versions of genes account for variations in inherited characters. This is the concept of alleles. Alleles are different versions of genes that impart the same characteristic. Each human has a gene that controls eye color, but there are variations among these genes in accordance with the specific color the gene "codes" for. \nFor each characteristic, an organism inherits two genes, one from each parent. This means that when somatic cells are produced from two gametes, one allele comes from the mother, one from the father. These alleles may be the same (true-breeding organisms, e.g. ww and rr in Fig. 3), or different (hybrids, e.g. wr in Fig. 3). \nIf the two alleles differ, then one, the dominant allele, is fully expressed in the organism's appearance; the other, the recessive allele, has no noticeable effect on the organism's appearance. In other words, the dominant allele is expressed in the phenotype of the organism. However this does not always hold true: Today, we know several examples that disprove this "law", e.g. Mirabilis jalapa, the "Japanese wonder flower" (Fig. 3). This is called incomplete dominance. There is also codominance on a molecular level, e.g. people with sickle cell anemia, when normal and sickle-shaped red blood cells mix and prevent malaria. \nThe two genes for each character segregate during gamete production. This is the last part of Mendel's generalization. The two alleles of the organism are separated into different gametes, ensuring variation. \nDuring his experiments, Mendel encountered some traits that did not follow the laws he had encountered. These traits did not appear independently, but always together with at least one other trait. Mendel could not explain what happened and chose not to mention it in his work. Today, we know that these traits are linked on the same chromosome.\n\n[edit]\nMendel's law of independent assortment\nAlso known as Mendel's Second Law \nThe most important principle of Mendel's law of independent assortment is that the emergence of one trait will not affect the emergence of another. While his experiments with mixing one trait always resulted in a 3:1 ratio (Fig. 1) between dominant and recessive phenotypes, his experiments with mixing two traits showed 9:3:3:1 ratios (Fig. 2). Mendel concluded that each organism carries two sets of information about its phenotype. If the two sets differ on the same phenotype, one of them dominates the other. That way, information can be passed on through the generations, even if the phenotype is not expressed (F1 generations, figures 1 and 2).\n\nMendel's findings allowed other scientists to simplify the emergence of traits to mathematical probability. A large portion of Mendel's findings can be traced to his choice to start his experiments only with true breeding plants. He also only measured absolute characteristics such as color, shape, and position of the offspring. His data was expressed numerically and subjected to statistical
699803
There are two type of alleles: dominant and recessive.\n\nThe rule of dominance is basically that if dominant is present in the allele, the phenotype (appearance) will not show the recessive gene.\n\nIn Mendel's pea plant experiment, his dominant was purple flower  (PP) and recessive was white flower (pp). \nWhen he crossed purple with white, he got all purples, with genotype (gene) of Pp. Since purple is dominant and is present in genotype, the flower is purple.
695108
First you have to make out your alleles.  Your first parent PpLl will produce spermatozoids that can be either PL Pl pL pl.  As for the mother, she is also heterozygotous for both traits, so she is also PpLl and will produce eggs that are either PL Pl pL or pl.  The you make the Punnett square with all those four colomns and four rows.  You should get something like\n___|_PL__|_Pl_|_pL_|_pl__\nPL_|_PPLL|_PPLl_|_PpLL_|_PpLl_\nPl_|PPLl|_PPll_|_PpLl_|_Ppll_\npL_|PpLL_|_PpLl_|_ppLL_|_ppLl_\npl_|PpLl_|_Ppll_|_ppLl_|_ppll_\n\nOKAY NOW...\nPPLL means healthy all the way\nppll means has all the diseases\nIn between they are heterozygotous for one or both disease.\n\nSince you have 16 possibilities, then yes your 1/16 answer is correct for the probabilities of having both diseases\n\ncan you do the square for your second problem :-)
251834
mendel tested genes in peas. he cross bred smooth and wrinkled peas and found that all the offspring grew smooth. then he bred the offspring and they grew some smooth and some wrikled at a ratio of 3:1.\nthis maade him think about dominance, in this case, the smooth allele was dominant to the wrinkled allele. he also did work on smooth gen peas and wrinkled yellow peas. When he bred these, he found a ratio of 9(sreen smooth):3(green wrinlked):3(yellow smooth):1(yellow winkled). this showeed him that the green and smooth alleles were dominant to yellow and wrinkled.\nhe deided that the rules of breeding ratios would either be 9:3:3:1,3:1,2:1, or 1:1 when dealing with dominance
113257
The 2 genes are rather called alleles which means different forms of the same gene. One allele is dominant and the other one is recessive. The one that is expressed is the dominant one and the hidden one is recessive. The organism is said to be heterozygous or hybrid.
588883
Identical twins have identical genes, so hereditary affects would show up in both twins.  They would both have the same eye color and hair color for example.  If there is a difference between the twins, then there is not a genetic link or the genetic link is weak enough that environment influences the differences.\n\nFor example, there was an identical twin study done in Australia on 14,000 sets of identical twins.  One of the questions asked of the twins was about sexual orientation.  They found that if one twin was homosexual, 38% of the time his identical brother was too. For lesbianism the concordance was 30%.  If homosexuality was a pure genetic trait, then we would expect a number more like 100% as in the case of eye color and hair color.  The very low percentages in this large study would show that homosexuality has a very weak genetic link if there is any link at all.  So a twin study helped us to differentiate between whether homosexuality is hereditary or environmental.