Topic 3 - Deer Mice Case Study

Question 1

When making the link between genotype and phenotype, why is it important to establish whether alleles act independently or interact with one another to produce an adaptive trait?

Answer 1

The effect of mutations on the phenotype may be different depending on whether mutations interact in a complex way or whether they act independently (i.e. have an additive effect on the trait).

Question 2

How might mutations in (i) the protein-coding and (ii) the non-coding (regulatory) regions of a gene influence a phenotype?

Answer 2

If the mutation is in the protein-coding region, consequent changes in the structure or activity of the protein that the gene encodes may influence the phenotype of the individual in which the mutation has occurred. If a mutation occurs in a regulatory region, then alteration in phenotype may occur as a result of changes in the timing, location or extent of expression of the gene.

Question 3

What is a convergent trait?

Answer 3

A trait that evolves independently in individuals of different populations (i.e. individuals that are not closely related). Natural selection may favour the same trait (e.g. light coat colour) in different populations, so the trait can arise more than once.