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SémIDEEV

Bibliothèque de l’UMR « Évolution, Génomes, Comportement, Écologie »

EGCE – Bât. 13, campus CNRS, av. de la Terrasse,
91190 Gif-sur-Yvette

Vendredi  8  février 2019

12h00

Henrique TEOTONIO

Institut de Biologie de l'École Normale Supérieure

invité par Maud Tenaillon (GQE-Le Moulon) et Arnaud Le Rouzic (EGCE)

"Experimental evolution of locomotion in constant environments"

Abstract

Evolution with stabilizing selection is thought to be common in nature, and together with mutational input to explain in large part interspecific phenotypic variation, but empirical tests about how it directly determines trait distributions and their genetic architectures are few. The Caenorhabditis elegans Multiparental Experimental Evolution (CeMEE) panel of recombinant inbred lines is derived from a cross of multiple wild isolates and long-term experimental evolution at high populations sizes and under partial selfing, in a stable, constant and fairly unstructured laboratory environment.
We have phenotyped populations undergoing experimental evolution for 240 generations and the CeMEE lines derived from these populations for locomotion, using a high throughput protocol measuring hundreds of short-term time series at the time of reproduction for each of the thousands of individuals in each sample. In parallel we developed an inference model to estimate the transition probabilities among movement states (defined as forward, backward, and still states) such that with high accuracy we calculate the genetic variance-covariance matrices for these traits (G-matrices), while accounting for inbreeding depression.
We have further phenotyped mutation accumulation lines of two wild isolates obtained after 250 generations of evolution, isolates that are constituent founders of the CeMEE panel, in order to calculate mutation variance-covariance matrices. Using simulations we are testing the theory on the evolution of the G-matrices by genetic drift, mutation and/or selection.
Preliminary analysis indicates that genetic drift alone is insufficient to explain G-matrix evolution and that either mutation or selection are responsible for its reversion towards the standing genetic variation found among the wild isolate founders.