Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?

Question

Quizplus · Accepted Answer

The cross BbTt × BBtt results in offspring with genotypes: BBTt, BBtt, BbTt, and Bbtt. All offspring will have black fur (B is dominant). For long tails, only those with genotype tt will have long tails. The probability of tt is 1/2, so the fraction with black fur and long tails is 1/2.

Black Fur in Mice (B) Is Dominant to Brown Fur