Missions

Balancing selection is a form of natural selection that results in the maintenance of genetic diversity for a longer time than expected under neutrality. Its genomic signatures include an increase in genetic diversity within species, a decrease in divergence between species, an excess of intermediate allelic frequencies, and/or, for long-lived signals such as trans-species polymorphisms. Balancing selection can emerge from different non-exclusive evolutionary mechanisms: for example, heterozygote advantage (HA), negative-frequency dependent selection (NFDS) or spatially/temporally fluctuating selection (FS). Recently, new research showing that balancing selection is more common than previously thought started to accumulate, suggesting that balancing selection can play a significant role in the evolution of multiple regions throughout the genomes. However, most methods to detect balancing selection have been benchmarked only on scenario of HA. Yet, HA is thought to be a rare and transient mechanism that participates less than NFDS or FS in the maintenance of genetic polymorphisms. As a consequence, it is unclear whether existing genome scan methods are powerful enough to detect realistic dynamics of balancing selection, and how underestimated our view of balancing selection is.

In this context, we have launched the BalanSe ANR to better understand the importance of balancing selection in non-model organisms. This project will rely on a combination of simulations and empirical analyzes in four animal taxa: Pan/Homo (great apes), Ficedula (birds), Morpho (butterflies) and Coelopa (flies).

Activités

The recruited postdoc will first be in charge of assessing the power of current methods to detect balancing selection resulting from other mechanisms than HA, such as NFDS and FS using simulations. He/She will further explore new combinations of statistics, relying notably on haplotypes statistics provided by long-read data, to identify what are the most inclusive statistics, able to capture all mechanisms of balancing selection, and what are the most discriminatory ones, able to disentangle them. He/She will be responsible for the entire project, from designing the simulations to obtaining new combinations of statistics to writing articles. He/She could also supervise master's students on specific sub-projects.

Compétences

The postdoc should have a PhD degree in evolutionary biology, with expertise in bioinformatics, statistics, programming and/or modeling. Previous expertise in population genomics or motivation to learn these concepts would be highly appreciated.
The postdoc should be able to make his/her work easily accessible and reusable by others following FAIR practices, or be willing to learn how to do so.
As in all research work, the postdoc should have good communication skills to synthesize his/her work and present it both in oral presentations and for scientific writing, all in English.

Contexte de travail

The postdoc is part of a 4-year collaborative ANR project between the LBBE (Lyon, France), the CIRB (Paris, France) and ECOBIO (Rennes France). The postdoc will join the CIRB (Centre Interdisciplinaire de Recherche en Biologie) under the supervision of Violaine Llaurens or the LBBE (Laboratoire de Biométrie et Biologie Evolutive) under the supervision of Laure Ségurel, depending on the candidate preferences. This project will also be carried out in close collaboration with Sylvain Glémin (ECOBIO, Rennes).
Both work environments offer a stimulating scientific environment and will provide access to computing clusters.