Date de publication : Sep 20, 2013 2:19:58 PM
Our project SEAD ( How does SElfing affect ADaptation: Genetic and demographic effects ) will be funded by the ANR (BioAdapt program) 2014 - 2018.
2 postdoc positions will be available in 2014 (see Job offers)
Summary
The ability for a population to adapt to environmental changes depends on several factors such as its size,
genetic diversity, or mating patterns, in particular selfing rates. In flowering plants, mating patterns are
highly variable from strict outcrossing to predominant selfing and almost a half self-fertilize at various rates.
Nevertheless, random mating is a classic assumption and the effect of selfing on adaptation remains largely
unresolved: on the one hand, the young age of selfing lineages suggests that selfing species lose the ability to
adapt to changing environments; on the other hand, the large proportion of selfers in crops suggests that
selfing could facilitate adaptation to human use. Selfing can indeed have multiple and complex effects. It
shapes the genetic variance of a population, but also the interaction between selection and drift or migration.
Selfing is also likely to alter population’s demography, because inbreeding and outbreeding depressions
affect the vital rates of individuals. Both these genetic and demographic impacts bear upon the probability of
adaptation to environmental variation, which depends on a race between the speed of the adaptive process
and the speed of population decline. A refined understanding of these impacts is therefore essential to predict
the fate of selfing species in the current context of global change and to improve conservation and
management strategies of both natural and cultivated populations.
In this project, we propose to tackle three main issues regarding the effect of selfing on adaptive
processes, through a combination of theoretical developments and fine scale analyses of three species. Our
study systems include two predominantly selfing and one partially selfing species, all undergoing adaptation
to environmental changes related to human activities. First, we propose to focus on the response to selection
within population, by developing models explicitly taking into account the complex genetic architecture of
traits and specific selection regimes. This modelling approach will be combined with the temporal
monitoring of experimental or natural populations under selection. Secondly, we will examine how selfing
affects local adaptation in populations connected by gene flow. To achieve this, we will analyse the interplay
between selection, drift and gene flow under partial selfing to predict the rate of phenotypic divergence and
to quantify local adaptation to heterogeneous environments. Thirdly, we will investigate how temporal
variations in selfing rates modify the dynamics of adaptation, while explicitly taking into account
demographic effects (especially inbreeding depression and reproductive assurance). This proposal unites
research groups that have long been addressing related questions and have complementary expertise (e.g.
ecology, demography, population and quantitative genetics, evolutionary theory, crop science).