Haiti is settled by peoples of both African and European ancestry. A young couple, both with mixed ancestry, marry and have several children. The children vary widely in the amount of skin melanin production, with one child being lighter than both parents, and one being darker. The simple explanation for this is

A.) epistasis.

B.) multiple alleles are available for the one chromosomal locus that governs skin color.

C.) the environment affected the phenotype that developed.

D.) polygenic inheritance.

D.) polygenic inheritance.

Explanation:

Polygenic inheritance is a mode of inheritance wherein the single genetic trait is regulated by more than one gene. Here, the final phenotype of the individual depends on the sum total of the dominant alleles of all the genes involved in the regulation of that trait.

In the given example, a couple of mixed ancestries might have different genes in their genome for skin color. A combination of alleles of these genes in the progeny would produce new skin color which is not present in the parents. For example, a child with all the recessive alleles of the genes for melanin production would have very light skin color while a child with more dominant alleles would have darker skin.