A hypothetical combination of independently assorting genes

A hypothetical combination of independently assorting genes A-E determines percentage of fast and slow muscle twitch in humans. The combination AABbggDdee produces a potential collegiate miler, and the combination aaBBggDDee produces a potential collegiate sprinter. Two parents with mediocre running abilities have genotypes AaBbGgDDee and AaBbggDdEe. What are the chances that their first child will inherit genes for either a collegiate miler or sprinter? a. 1/128 b. 1/256 c. 3/128 d. 5/256

Solution

Chances of having AABbggDdee:

1/4 * 1/2 * 1/2 * 1/4* 1/2 = 1/128

Chances of having the genotype aaBBggDDee:

1/4* 1/4* 1/2 * 1/2* 1/2 = 1/128

So, the correct answer is a, (not c).