Lab-meeting: between-sex covariance for dummies explained by Tom Gosden

Posted by Erik Svensson

Next week, EXEB-member Tom Gosden will give a practice talk of his forthcoming Friday seminar about between-sex covariance and genetic constraints on the evolution of sexual dimorphism.

As many of you already know, Tom is a former PhD-student in our laboratory, and is currently visiting postdoc, until he will return to Brisbane in Australia where he will commence a Junior Research position.

Tom's informal talk will be about fruitflies (Drosophila) and how to understand, interpret and estimate between-sex genetic covariance, and Tom has promised to explain it also to non-experts. Note that the lab-meeting time has been changed to afternoon from morning and to another locality on 3rd floor. For those of you who want to get a deeper idéa what Tom's research is about, here is a link to a recent article he published in Evolution.

When: Tuesday March 4 2014, 14.00-15.30
Where: Seminar room "Communis", 3rd floor (Ecology Building)

 Everybody should be most welcome!

THE B-MATRIX HARBORS SIGNIFICANT AND SEX-SPECIFIC CONSTRAINTS ON THE EVOLUTION OF MULTICHARACTER SEXUAL DIMORPHISM 

Thomas P. Gosden, Krishna-Lila Shastri, Paolo Innocenti, Stephen F. Chenoweth

The extent to which sexual dimorphism can evolve within a population depends on an interaction between sexually divergent selection and constraints imposed by a genetic architecture that is shared between males and females. The degree of constraint within a population is normally inferred from the intersexual genetic correlation, rmf. However, such bivariate correlations ignore the potential constraining effect of genetic covariances between other sexually coexpressed traits. Using the fruit fly Drosophila serrata, a species that exhibits mutual mate preference for blends of homologous contact pheromones, we tested the impact of between-sex between-trait genetic covariances using an extended version of the genetic variance–covariance matrix, G, that includes Lande's (1980) between-sex covariance matrix, B. We find that including B greatly reduces the degree to which male and female traits are predicted to diverge in the face of divergent phenotypic selection. However, the degree to which B alters the response to selection differs between the sexes. The overall rate of male trait evolution is predicted to decline, but its direction remains relatively unchanged, whereas the opposite is found for females. We emphasize the importance of considering the B-matrix in microevolutionary studies of constraint on the evolution of sexual dimorphism.