Research Group Space
paco.garcia[at]ebd.csic.es

Evolvability of fitness, sexual and reproductive traits

Publications filtered by: Evolvability of fitness, sexual and reproductive traits

No evidence for heritability of male mating latency or copulation duration across social environments in Drosophila melanogaster
Taylor, M. L., Evans, J. P. and Garcia-Gonzalez, F. 2013 No evidence for heritability of male mating latency or copulation duration across social environments in Drosophila melanogaster PLoS ONE, 8:e77347
Abstract
A key assumption underpinning major models of sexual selection is the expectation that male sexual attractiveness is heritable. Surprisingly, however, empirical tests of this assumption are relatively scarce. Here we use a paternal fullsib/half-sib breeding design to examine genetic and environmental variation in male mating latency (a proxy for sexual attractiveness) and copulation duration in a natural population of Drosophila melanogaster. As our experimental design also involved the manipulation of the social environment within each full-sibling family, we were able to further test for the presence of genotype-by-environment interactions (GEIs) in these traits, which have the potential to compromise mate choice for genetic benefits. Our experimental manipulation of the social environment revealed plastic expression of both traits; males exposed to a rival male during the sensitive period of adult sexual maturation exhibited shorter mating latencies and longer copulation durations than those who matured in isolation. However, we found no evidence for GEIs, and no significant additive genetic variation underlying these traits in either environment. These results undermine the notion that the evolution of female choice rests on covariance between female preference and male displays, an expectation that underpins indirect benefit models such as the good genes and sexy sons hypotheses. However, our results may also indicate depletion of genetic variance in these traits in the natural population studied, thus supporting the expectation that traits closely aligned with reproductive fitness can exhibit low levels of additive genetic variance.
Comparing evolvabilities: Common errors surrounding the calculation and use of coefficients of additive genetic variation
Garcia-Gonzalez, F., Simmons, L. W., Tomkins, J. L., Kotiaho, J. S. & Evans, J. P. 2012 Comparing evolvabilities: Common errors surrounding the calculation and use of coefficients of additive genetic variation Evolution, 66:2341-2349
Abstract

In 1992 David Houle showed that measures of additive genetic variation standardized by the trait mean, CVA (the coefficient of additive genetic variation) and its square (IA), are suitable measures of evolvability. CVA has been used widely to compare patterns of genetic variation. However, the use of CVAs for comparative purposes relies critically on the correct calculation of this parameter. We reviewed a sample of quantitative genetic studies, focusing on sire models, and found that 45% of studies use incorrect methods for calculating CVA and that practices that render these coefficients meaningless are frequent. This may have important consequences for conclusions drawn from comparative studies. Our results are suggestive of a broader problem because miscalculation of the additive genetic variance from a sire model is prevalent among the studies sampled, implying that other important quantitative genetic parameters might also often be estimated incorrectly. We discuss the most prominent issues affecting the use of CVA and IA, including scale effects, data transformation, and the comparison of traits with different dimensions. Our aim is to increase awareness of the potential mistakes surrounding the calculation and use of evolvabilities, and to compile general guidelines for calculating, reporting and interpreting these useful measures in future studies.

Pages