The evolution and genomics of female-limited polymorphisms through sexual conflict over mating

Visite des infrastructures de la SETE après le séminaire

• 10:30 - Accueil
• 11:00 - Séminaire d'Erik
• 12:00 - Repas
• 13:30 - Visites des infrastructures : terrestrial metatron, aquatic metatron, grottes, serres et volières

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Résumé

Female-limited polymorphisms (e. g. colour polymorphisms) are increasingly documented in many taxa, including insects, but also in vertebrates like lizards and birds. How and why such female-limited polymorphisms have evolved, their adaptive significance, genomic basis and phylogenetic history is gaining increased attention. Here, I will provide an overview of the evolution of such female-limited polymorphisms, with a focus on damselflies of the genus Ischnura, illustrating with research from my own lab and from other groups. Female-limited colour polymorphisms occur in several species of Ischnura and have evolved independently up to five times. One of the female morphs is male-limited in colouration (“andromorph females”) and benefits from male mimicry and reduced male mating harassment. Male search images are plastic, as revealed by opsin gene expression profiles that vary with local female morph frequencies. Plastic male mate preferences drive negative frequency-dependent selection (NFDS) that preserves these female polymorphisms over both micro- and macroevolutionary time scales. Our recent phylogenetic and genomic research revealed that these trans-species polymorphisms are at least 5 million years old, are shared between closely related species and arise from a major effect locus on chromosome 13, which shows chromosome-level reduced recombination and a high density of Transposable Elements (TE:s). Male-mimicking females arose in a background of female monomorphism and sexual dimorphism through a chromosomal inversion, followed by genomic expansion of the nascent morph locus, accumulation of TE:s and reduced recombination. The morph locus shows molecular signatures of long-term balancing selection (Tajima’s D). I will synthesize these findings from ecology, phylogenetics and genomics that have jointly uncovered the microevolutionary processes and macroevolutionary history of these polymorphisms.

Publications liées :
https://www.nature.com/articles/s41559-023-02243-1
https://www.sciencedirect.com/science/article/pii/S1055790321000671