1) Yellow coat color in mice is dominant, and a mouse carrying a dominant (Y) al
ID: 192340 • Letter: 1
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1) Yellow coat color in mice is dominant, and a mouse carrying a dominant (Y) allele at the yellow gene will always be yellow, no matter what alleles they have at other genes. Another gene, "E", determines if a mouse will be black or brown in color, with black (E) dominant to brown. a. What type of genetic interaction best describes the effect of the yellow gene in mice? Dominant Epistass b. A yellow male mates with a brown female, and they produce a surviving black and brown offspring. What is the genotype of the four individuals (use ? for any alleles you cannot determine)? Yellow father Brown mother Black offspring Brown offspring c. The same yellow male is mated to a yellow female. They produce a litter with the following surviving offspring: 8/12 yellow, 1/12 brown, 3/12 black. Based on this information, what is the genotype of each offspring class and the yellow mother? (use ? for any alleles you cannot determine)? Yellow mother Black offspring Yellow offspring Brown offspring 2) You are mapping genes in a species of fruit fly. You cross a wild type fly to a fly from a true-breeding mutant strain with green eyes (g), short wings (sw), and hairy legs (hl). The FI progeny all appear wild type (red eyes, long wings, smooth legs). You then testeross a female FI fly to a male from the mutant strain, and obtain 200 progeny 20 green, short, hairy red, long, smooth green, long, smooth green, short, smooth 44 red, short, hairy 42 red, long, hairy 20 green, long, hairy 5 red, short, smooth 30 32 a. What are the genotypes of the two flies in this testcross? b. How many progeny of each phenotype would be expected from this cross if the genes were assorting independently? green, short, hairy red, long, smooth green, long, smooth green, short, smooth red, short, hairy red, long, hairy green, long, hairy red, short, smoothExplanation / Answer
a. Dominant epistasis:
A single dominant allele at one locus supresses the effect by other interacting genes irrespective of their allelic status (Dominant or recessive).
b.
Y_ _ _ = Yellow
yy E_ = Black
yy ee = Brown
Parental cross: YyEe (Father) X yyee (mother)
Gametes: (YE)(Ye)(yE)(ye) X (ye)
Progeny: YyEe Yyee yyEe yyee
YyEe and Yyee = Yellow
yyEe = Black
yyee = Brown
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