Question

A new mutation arises that is recessive. What must occur before selection can act on this allele?

Options

• The allele must increase in frequency through differential mortality

• The allele must convert into a dominant form through further mutation

• The allele must spread through the entire gene pool first

• The allele must be inherited in a homozygous state and expressed in the phenotype

Answer 1

Recessive alleles remain hidden from selection until they are inherited in a homozygous state and are finally expressed in the phenotype. Only then can selection act on the allele based on the phenotypic advantage or disadvantage it confers.