Coat color in mice can show many varieties. You have two true-breeding mouse sta
ID: 13059 • Letter: C
Question
Coat color in mice can show many varieties. You have two true-breeding mouse stains, one with white fur; the other with black fur. Upon crossing a male and female of both strains, you find that all of the offspring show the agouti coat color: agouti is best described as a layered brown colorUpon crossing agouti males and females, you observe the following traits: 450 agouti mice, 150 mice with black fur, and 200 mice with white fur.
Are these results best explained by one gene with three alleles or two genes, each with two alleles? Explain your answer using allele symbols to represent the F1 and F2 results
Explanation / Answer
Coat color in mice can show many varieties. You have two true-breeding mouse stains, one with white fur; the other with black fur. Upon crossing a male and female of both strains, you find that all of the offspring show the agouti coat color: agouti is best described as a layered brown color
white furWW x BB black fur
GAMETES W, W B B
OFFSPRING---------WB agouti ---------F1 GENERATION
WB agouti X WB agouti
WW---------200 mice with white fur.
WB ,WB----------450 agouti mice
BB------150 mice with black fur
OBSERVED RATIO-- 1(200) :2( 450) :1(150)
EXPECTED RATIO 1(200) :2( 400) :1(200)
THERE IS DEVIATION FROM HARDY WEINBERG EQUILIBRIUM
TWO GENE INVOLVED
INCOMPLETE DOMINANCE