Is "good genes" dead?

Posted by Jessica Abbott

A classic example of sexually selected traits. Picture by Fir0002/Flagstaffotos.

Since we're going to have guests at our next group meeting (see previous post), I thought it might be nice to read a paper about something that all of us have a common interest in: sexual selection. I think this paper has actually come up in conversation a few times during our meetings, but as far as I can tell it's never been chosen as a discussion paper. It's a meta-analysis of sexual selection studies that shows that Fisherian models of sexually selected traits have much better empirical support than good genes theories.

10.30-12.00 on Tuesday May 13th in Argumentet.

Title: Meta-analysis suggests choosy females get sexy sons more than "good genes"
Abstract: Female preferences for specific male phenotypes have been documented across a wide range of animal taxa, including numerous species where males contribute only gametes to offspring production. Yet, selective pressures maintaining such preferences are among the major unknowns of evolutionary biology. Theoretical studies suggest that preferences can evolve if they confer genetic benefits in terms of increased attractiveness of sons (“Fisherian” models) or overall fitness of offspring (“good genes” models). These two types of models predict, respectively, that male attractiveness is heritable and genetically correlated with fitness. In this meta-analysis, we draw general conclusions from over two decades worth of empirical studies testing these predictions (90 studies on 55 species in total). We found evidence for heritability of male attractiveness. However, attractiveness showed no association with traits directly associated with fitness (life-history traits). Interestingly, it did show a positive correlation with physiological traits, which include immunocompetence and condition. In conclusion, our results support “Fisherian” models of preference evolution, while providing equivocal evidence for “good genes.” We pinpoint research directions that should stimulate progress in our understanding of the evolution of female choice.