科研之友
微信
新浪微博
Facebook
分享链接
摘要
Understanding the relative influence of genetic drift and selection is fundamental in evolutionary biology. The theory of neutrality predicts that the genetic differentiation of a quantitative trait (Q(ST)) equals the genetic differentiation at neutral molecular markers (F-ST) if the quantitative trait has not been under selection. Thus, the relative magnitude of observed Q(ST) and expected Q(ST) under neutral expectations suggests the importance of selection and genetic drift for any observed phenotypic divergence. Because Q(ST) is based on additive genetic variance, estimating Q(ST) based on phenotypic measurements is problematic due to unknown environmental effects. To account for this, we used a model where the environmental component was allowed to vary when estimating Q(ST). The model was used on data from 14 house sparrow (Passer domesticus) populations in Norway. In accordance with the significant phenotypic inter-population differences our analyses suggested that directional selection may have favoured different optimal phenotypes for some morphological traits across populations. In particular, different body mass and male ornamental phenotypes seemed to have been favoured. The conclusions are, however, dependent on assumptions regarding the proportion of the observed inter-population variation that is due to additive genetic differences, showing the importance of collecting such information in natural populations. By estimating Q(ST), allowing the additive genetic proportion of phenotypic inter-population variation to vary, and by making use of recent statistical methods to compare observed Q(ST) with neutral expectations, we can use data that are relatively easy to collect to identify adaptive variation in natural populations.
- 出版日期2011-10
