Could someone please help me with this homework problem? I\'mthinking that the w
ID: 5033 • Letter: C
Question
Could someone please help me with this homework problem? I'mthinking that the white eye gene and the red eye gene operates byepistasis. White is the epistatic gene and red is the hypostaticgene, and it is recessive epistasis. I don't know though I'mconfused. Would white be epistatic to all the colors? PleaseHelp!!! Which of the eye color phenotypes infruit flys: wild type, scarlet, brown and white, operate viaepistasis? Is it dominant or recessive? Which is the epistaticphenotype and which is the hypostatic? Describe the F1 and F2 crossthat shows this this epistasis. Could someone please help me with this homework problem? I'mthinking that the white eye gene and the red eye gene operates byepistasis. White is the epistatic gene and red is the hypostaticgene, and it is recessive epistasis. I don't know though I'mconfused. Would white be epistatic to all the colors? PleaseHelp!!! Which of the eye color phenotypes infruit flys: wild type, scarlet, brown and white, operate viaepistasis? Is it dominant or recessive? Which is the epistaticphenotype and which is the hypostatic? Describe the F1 and F2 crossthat shows this this epistasis.Explanation / Answer
In Drosophila the locus for eye color is located on theX chromosome. It is not a case of epistasis.
The allele for red eye color, which is normal in wild flies, isdominant to the mutant allele for white eyes.
As females have two chromosomes X (with a locus for eye color),they might be homozygous or heterozygous for either allele.
Males, who carry only one X chromosome, are always hemizygous. Theycarry only the one X chromosome inherited from their mother, and itdetermines their eye color.
Cross a homozygous white eyed male with a homozygous red eyedfemale, and all the offspring have red eyes. Red is dominant overwhite. However, cross a homozygous white eyed female with a redeyed male, and the unexpected results show all the males have whiteeyes and all the females red eyes. This can be explained if the eyecolor gene is on the X chromosome.
If the gene for eye color is on the X chromosome, the red eyedmale in the second cross will pass his red eyed X to only hisdaughters, who in turn received only a recessive white-carrying Xfrom their mother. Thus all females had red eyes like their father.Since the male fruit fly passes only the Y to his sons, their eyecolor is determined entirely by the single X chromosome theyreceive from their mother (in this case white). Thus all the malesin the second cross were white eyed.
These experiments introduced the concept of sex-linkage, the occurrence of genes onthat part of the X that lack a corresponding location on the Y.
Eye color in Drosophila is a complex trait influencedby genes of many different types. The Drosophila eye hastwo classes of pigments contained in it, ommochromes andpteridines
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.