Mendel discovered that whether his peas were yellow or green is determined by a single gene in which yellow (Y) is dominant over green (y). Assuming low selective pressure, what does the Hardy-Weinberg Equilibrium frequency term 2pq represent in the peas?

Heterozygous, Yy

Explanation:

According to Hardy-Weinberg equilibrium, the allele frequencies remain constant in a population in absence of an evolutionary force like genetic drift or natural selection. Since here the population is under low selective pressure, it can be considered almost in Hardy-Weinberg equilibrium. According to it,

p + q = 1

p² + 2pq + q² = 1 where,

p = frequency of dominant allele = f(Y)

q = frequency of recessive allele = f(y)

p² = frequency of homozygous dominant genotype = f(YY)

2pq = frequency of heterozygous genotype = f(Yy)

q² = frequency of homozygous recessive genotype = f(yy)

Hence, the term 2pq represents the frequency of heterozygous Yy peas.