Question

Two genes, A and B, are located 30 map units apart. The dihybrid shown below is mated to a tester aa bb. What proportion of the offspring is expected to be dominant for both traits?

a) 1/16
b) 1/8
c) 1/4
d) 1/2

Answer 1

The proportion of offspring that are dominant for both traits is 9/16.

Step-by-step explanation:

The proportion of offspring that are dominant for both traits can be calculated using the product rule. The probability of a homozygous dominant at gene A is 1/4 and the probability of a heterozygote at gene A is 1/2. The same probability can be obtained for gene B. Therefore, the probability of a dominant phenotype at both genes A and B is equal to (3/4) x (3/4), or 9/16.