# Human skin color is determined by the interaction of several pairs of genes according to the type of cumulative polymer

Human skin color is determined by the interaction of several pairs of genes according to the type of cumulative polymer, that is, the darker the skin color, the more dominant genes in the genotype. Let’s say skin color is determined by two pairs of non-allelic genes. Different combinations of genes can form five phenotypes: blacks (A1A1A2A2), dark mulattos (A1a1A2A2, A1A1A1a2), medium mulattos (a1a1A2A2, A1A1a2a2, A1a1A2a2), light mulattos (A1a1a2), light mulattos (A1a1a2)
1) What kind of children and in what proportion can be expected from the marriage of a black woman and a white man?
2) What is the probability of the birth of blacks and white children from the marriage of two diheterozygous middle mulattoes?
3) What is the probability of the birth of lighter children among spouses – dark mulattoes?
4) Mother is a light mulatto, father is a dark mulatto. What is the probability of the birth of children in this marriage – middle mulattoes?

1) All children from the marriage of a black woman and a white man will be average mulattoes;
2) the probability of birth from marriage of two diheterozygous middle mulatto blacks – 1/16, white children – 1/16;
3) the probability of having lighter children among spouses – dark mulattoes – 25%;
4) the probability of the birth of children – average mulattos from the marriage of a light mulatto and a dark mulatto:
a) 25%, if the parents are homozygous for the same pair of genes (mother for a recessive trait, father for a dominant one) and heterozygous for the other;
b) 50%, if the parents are heterozygous for different pairs of genes, and the other pair for each parent is homozygous (for the mother for a recessive trait, for the father for a dominant one).

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