[COLLOQUE] GENTREE Final Conference 27-31 January 2020 séance 15

GENTREE Final Conference : Claire GODINEAU - University of Montpellier · France 

GENTREE Final Conference 'Genetics to the rescue - managing forests sustainably in a changing environment'

27-31 January 2020, Avignon, France

http://www.gentree-h2020.eu/

Claire GODINEAU - University of Montpellier · France : A theoreticalstudy of the effects of assortative mating on the adaptive potentialunder climate change

Rapid evolutionary responses to contemporary climate change have been measured mostly for phenological traits, especially flowering times.

Flowering times of mates have to be similar for reproduction to take place, and are thus under assortative mating. Compared to random mating, assortative mating is predicted to increase the geneticvariance of polygenic traits at mutation-genetic drift equilibrium,and to increase evolutionary response to directional selection.

We lack quantitative predictions about the effect of assortative matingon adaptive potential under scenarios of selection that mimic climate change.

We here built an individual-based quantitative genetics model to compare the adaptive potential of a polygenic trait under random versus assortative mating.

We analyzed equilibrium genetic varianceand mean population fitness for several selection regimes defined byintermediate to strong stabilizing selection, combined with aconstant moving optimum and inter-generational fluctuations of the optimum.

For a stationary environment with uncorrelated fluctuationsand moderate to strong selection, assortative mating does notfacilitate adaptation of populations compared to random mating. Incontrast, when the optimum changes directionally with fluctuations around this trend, thus mimicking climate change, assortative mating in creases genetic variance, which decreases the lag to the optimumand increases mean population fitness.

The fitness advantage ofassortative mating increases with the speed of change of the optimum.

Comparison to analytical predictions shows that the adaptiveadvantage of assortative mating is entirely explained by the evolution of larger genetic variances.

The fitness advantage ofassortative mating decreases when the genetic variance becomes less limiting for adaptation, e.g. when the number of loci or the intensity of stabilizing selection increases.

Therefore, in the context of climate change, assortative mating should allow better tracking of changing environments than should random mating and may contribute to rapid evolution of phenological traits.