Question

What fraction of offspring of the cross AabbDd x AaBbDd are expected to have the

same phenotype as either one or the other of their parents assumingthat all three
genes are on different chromosomes?
A. 18/64
B. 24/64
C. 9/64
D. 36/64
E. none of the above

Answer 1

Answer: E. none of the above

Explanation:

given data:

AabbDd x AaBbDd

For gene A, there will be cross of Aa X Aa. The probability of having a phenotype, that is either AA or aa is 2/4 = 1/2

For gene B, there will be cross of Bb X BB. The probability of having a phenotype, that is BB is 1/4

For gene D, there will be cross of Dd X Dd The probability of having a phenotype, that is either DD or dd is 2/4 = 1/2.

Hence, the probability of the off spring having all the genes.

= 1/2 * 1/4 * 1/2

= 1/16