Question

D 26. Why do we expect to see more synonymous substitutions than non-synonymous substitutions if a locus is under purifying selection? In your answer, be sure to explain what synonymous vs. non-synonymous substitutions and purifying selection are. Enter answer... D27 In some birds such as phalaropes, males provide all of the parental care to offspring, and females compete with one another for access to males and breeding territory. In this species, would you expect males or females to be larger and more brightly colored (or would they be the same)? Explain your answer. Enter answer...

Answer 1

26. Synonymous mutation = A mutation that replaces an amino acid with another amino acid that exhibits similar structure and biochemical properties.
Ex: Asp ---> Glu
Asn ----> Gln
Leu ----> Ile

Non-synonymous mutation = A mutation that replaces an amino acid with another amino acid that exhibits a different structure and biochemical properties.
Ex: Asp ---> Lys
Asn ----> Trp
Leu ----> Ser

Purifying selection = Stabilizing selection that eliminates all the deleterious alleles from a population

A purifying selection allows for synonymous mutations as they do not significantly alter the protein function.

27. In sexual selection, the competitor has to spend energy to attract the opposite gender.
In the given case, females are competing for males.
So, females should be attractive i.e. large and brightly colored.