Question

certain ocean crabs exoskeleton color is polygenic with each dominant allele adding additional pigment. in the ocean, darker crabs are harder to see and are more easily able to avoid predators. which genotype below would be the most successful in this environment?

• aabbcc
• aabbcc
• aabbcc
• aabbcc

Explanation:

The trait (exoskeleton color) is polygenic, with each dominant allele adding more pigment, making the crab darker. Darker crabs avoid predators better, so the genotype with the most dominant alleles will be most successful. Count dominant alleles for each option:

• AaBbCc: 3 dominant alleles
• aabbCC: 2 dominant alleles
• Aabbcc: 1 dominant allele
• AABBCC: 6 dominant alleles

AABBCC has the most dominant alleles, resulting in the darkest color and highest survival success.

Answer:

D. AABBCC