AP BIOLOGY

Detailed explanation-1: -Brown mice have the genotype BB or Bb.

Detailed explanation-2: -This Bb genotype is termed as heterozygous. A heterozygous genotype is when the genes that an offspring receives are different, Bb. In this instance, dominance will also be expressed because the offspring will have the dominant trait of brown hair.

Detailed explanation-3: -Tutorial. The expected genotype ratio when two heterozygotes are crossed is 1 (homozygous dominant) : 2 (heterozygous) : 1 (homozygous recessive).

Detailed explanation-4: -First, let’s provide gene symbols. From the above discussion, the genotype of the gray mouse must be yy. What is the genotype of the yellow mouse? If the mouse was homozygous we would not see any gray mice from the cross, therefore the genotype must be heterozygous or Yy.