Genetics homework help?

Just 3 problems I'm having a little trouble with:





In the fruit fly, vestigial wings and hairy body are produced by recessive alleles on to different chromosomes. If a vestigial winged, hairy male is crossed with a homozygous normal female, what ratios of phenotype and genotype do you expect in the F1 and F2 generations?








When two short-tailed cats mate, about half of the kittens have short tails, a quarter have long tails, and a quarter have no tails. What is the simplest genetic explanation for the inheritance of this trait?








In peas, the allele for tall plants (T) is dominant over the allele for short plants (t). On a separate chromosome, the allele for smooth peas (S) is dominant over the allele for wrinkled peas (s). Calculate phenotypic ratios for the following crosses:


a. TtSs x TtSs


b. TtSs x ttss


c. ttSs x Ttss


d. TTss x ttSS

Genetics homework help?
Here is a link to a Word document with the answers to the problems with explanations. Look at problem numbers: 5, 6, and 11:





http://library.millsaps.edu/reserves/arm...
Reply:#1: recessive allele-v(vestigial); h(hairy)


normal: VVHH- homozygous


cross: VVHH with vvhh


F1: phenotype 100% normal


genotype 100% geterozygous for both traits


F2: phenotype ratio is 9:3:3:1


#2: Because 50% of a genotype has short tail, this trait must be dominant(S). Possible options for cross:Ss or SS. Quarter of the offspring has no tails, therefore only cross between Ss and Ss can give such result.


#3: a. 9:3:3:1


b. 1:1:1:1


c.1:1:1:1


d. 100% tall with wrinkled peas