Question

Why are alleles present in homozygous recessive organisms exposed to environmental selection?

Options

• Environmental factors only affect homozygous individuals

• Recessive alleles mutate more rapidly in homozygous conditions

• Only alleles in homozygous recessive organisms are expressed in the phenotype and thus exposed to environmental selection

• Homozygous recessive organisms reproduce more frequently

Answer 1

Alleles in homozygous recessive organisms are expressed in the phenotype because there is no dominant allele to mask them. This expression makes them visible to environmental selection and potentially subject to elimination if the phenotype is disadvantageous.