In a population of plants, the allele for long stems is completely dominant over the allele for short stems. If 35% of the population has short stems, calculate the percentage of the population that is expected to be heterozygous

Assumptions:

1. Equilibrium has been reached for the allele proportions

2. Absence of evolutionary influences such as mate choice, mutation, selection, genetic drift, gene flow and meiotic drive.

Defining L=long stem, l=short stem, and L is dominant over l.

f (x) = frequency of allele x (expressed as a fraction of population)

Then the Hardy-Weinberg equilibrium law applies:

p^2+2pq+q^2=1

where

f (LL) = p^2

f (Ll) = 2pq

f (ll) = q^2

Given f (ll) = 0.35=q^2, we have

q=sqrt (0.35) = 0.591608

p=1-q=0.408392

=>

f (Ll)

=2pq

=2*0.408392*0.591608=0.483216

= proportion of heterozygous population

Answer: percentage of heterozygous population is 48.32%