Black fur in mice is dominant to brown fur.Short tails is dominant to long tails.What proportion of the offspring from a cross between an individual with the genotype BbTt and BBtt will have black fur and long tails?
A) 1/16
B) 3/16
C) 6/16
D) 8/16
E) 9/16

Question

Quizplus · Accepted Answer

To solve this, we need to understand how each trait is inherited separately and then combine the probabilities. For fur color, B is dominant for black fur, so any offspring with at least one B allele will have black fur. The cross for fur color is between Bb (black fur) and BB (black fur), which means all offspring will have black fur because they will all inherit at least one B allele. For tail length, T is dominant for short tails, and the cross is Tt (short tail) and tt (long tail), which follows a Mendelian 1:1 ratio for Tt (short tail) and tt (long tail) in the offspring. Since we are looking for black fur and long tails, we focus on the tt outcome for tails, which is 1/2 of the offspring, and since all offspring have black fur, the proportion with black fur and long tails is 1/2, or 8/16.

Black Fur in Mice Is Dominant to Brown Fur