Question

A population of pea plants has 25% dwarf plants and 75% tall plants. the tall allele, t, is dominant to dwarf (t). what percentage of tall plants is heterozygous?

Answer 1

Here we would be using Hardy Weinberg equation for the calculation of allele and genotypic frequencies.

Dwarf genotype frequency = $q^{2}$ = 25% = 0.25

Frequency of allele t = q = $\sqrt{q^{2}}$ = $\sqrt{0.25}$ = 0.5

According to the equation,

p + q = 1

p = 1 - 0.5 = 0.5

Now, the frequency of heterozygous tall plants would be-

2pq = 2 * 0.5 * 0.5 = 0.5 or 50% heterozygous tall plants.