AP BIOLOGY

HEREDITY

MONOHYBRID CROSS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Brown hair is dominant to gray hair in mice. Determine the genotype and phenotype ratios for a homozygous recessive female and a homozygous recessive male.
A
2:4 Bb 2:4 bb2:4 brown hair 2:4 gray hair
B
2:4 BB 2:4 bb2:4 brown hair 2:4 gray hair
C
4:4 Bb4:4 brown hair
D
4:4 bb4:4 gray hair
Explanation: 

Detailed explanation-1: -Brown mice have the genotype BB or Bb. White mice have the genotype bb. The frequency of the BB genotype is 0.30.

Detailed explanation-2: -So, we can say that B denotes the dominant trait and b denotes the recessive trait. As black hair are dominant over brown hair, we can assume the possible genotypes for black hair to be BB or Bb. Likewise the genotype for brown hair will be bb.

Detailed explanation-3: -Most people have two functioning copies of the MC1R gene, one inherited from each parent. These individuals have black or brown hair, because of the high amount of eumelanin. It is estimated that more than 90 percent of people in the world have brown or black hair.

Detailed explanation-4: -Hair color is a genetic and physiologically complex phenotype, which represents one of the most visible variations within humans and between populations [1].

There is 1 question to complete.