Question

There are 127 offspring from a cross of AaBb x AaBb. If Mendelian ratios are followed, how many offspring would you expect to have recessive phenotypes for both traits?

Answer 1

Answer: 8

Explanation: 127 divided by 16 which is how many boxes you have in your punnet square is 7.9 so just round and it gives you 8!

Answer 2

eight (8)

Explanation:

A phenotypic ratio of 9:3:3:1 is predicted from a cross of AaBb x AaBb (i.e., in a dihybrid cross). In this case, the expected phenotypic ratio is equal to:

A_B_ (9:3:3:1) =71.43 >> 71 both dominant phenotypes

aaB_ (9:3:3:1) = 23.81 >> 24 one dominant phenotype

A_bb (9:3:3:1) = 23.81 >> 24 one dominant phenotype

aabb (9:3:3:1) = 7.93 >> 8 both recessive phenotypes

Expected phenotipic ratio (9:3:3:1) = 71 + 24 + 24 + 8 = 127