Both male and female rats have genotype bb. based on the punnett square, carol concluded that the phenotypic ratio of the monohybrid cross is 2: 1: 1. what mistake did carol make? a) the ratio should be 2: 1 b) the ratio should be 3: 1 c) the ratio should be 2: 1: 1 d) the ratio should be 1: 1: 1: 1

Answer: The ratio should be 3:1.

Explanation:

When the male and female rates with genotype Bb are crossed we get,

Bb X Bb > BB Bb Bb bb

Since B is dominant over b, the offsprings with genotype BB and Bb will have dominant phenotype and the ones with bb will have recessive phenotype. Since 3 offsprings have dominant phenotype as seen from the cross (One BB and 2 Bb) and one has a recessive phenotype (bb) the phenotypic ratio would be 3: 1.

Where are the following choices