If grey feathers is a recessive trait, then 72.8% of the population is heterozygous for this trait.
Explanation:
The concept used here is of Hardy Weinberg principle, [tex]p^{2} + q^{2}[/tex] +2pq =1
The homozygous dominant genotypeis represented as [tex]p^{2}[/tex] = 84
Red = dominant
The homozygous recessive genotype trait is represented as [tex]q^{2}[/tex] = 16
grey = recessive
2pq = heterozygous individual
Thus for dominant homozygous the alleles are given as
p= [tex]\sqrt{84}[/tex]
= 9.1
q = [tex]\sqrt{16}[/tex]
= 4
for heterozygous individual 2pq
2 x 9.1 x 4
= 72.8
72.8% population is heterozygous for the trait.
