Evolutionary genetics: Sexually selected mutation rates

Think about this: If evolution ensures that ‘good’ genes spread through a population, then why don’t people get better and better looking through each generation and phase out ugliness?

A long-standing problem in evolutionary biology is whether females derive genetic benefits from mating with well-ornamented males. Male sexual ornaments are believed to be informative signals of male genetic quality as they exhibit condition-dependent expression, with condition being influenced by many loci in a male's genome. But persistent selection on ornaments and condition should cause genetic variation in male fitness to be depleted rapidly, thereby eliminating any advantage to female mate preference—a problem known as the 'lek paradox'. Recently, Petrie and Roberts (2006) proposed that female mate choice indirectly selects for elevated rates of mutation, and claim this increases the amount of available genetic variation faster than sexual selection can erode it. Their solution provides an intriguing resolution to the lek paradox, but can it really account for the maintenance of genetic variation in fitness associated with sexual ornaments?

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