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Accueil du site > Animations Scientifiques > Séminaires 2012 > Jos Käfer — Gender in plants : genomic consequences of dioecy in Silene

Jos Käfer — Gender in plants : genomic consequences of dioecy in Silene

Speaker

Jos Käfer, Laboratoire Biométrie et Biologie Évolutive, CNRS, UCB Lyon 1

When :

Wednesday 11 January at 11am

Where :

C023 (RDC LR6 côté Centre Blaise Pascal)

Title :

Gender in plants : genomic consequences of dioecy in Silene

Abstract :

Dioecy (i.e. having separate sexes) is a way to prevent self-fertilization, and is thus supposed to improve the efficacy of selection in a species. However, in flowering plants, dioecy is a rare breeding system, and dioecious species are thought to have a high probability of extinction. We try to disentangle the different effects that dioecy could have on species evolution using sequences from the Silene genus (Caryophyllaceae), where dioecy has evolved at least twice. In section Melandrium, where dioecy is the oldest, we found clear evidence for a reduced efficacy of selection, while no differences are found for the more recently dioecious section Otites. In sect Melandrium, we also found a signal of positive selection in the nuclear genome, which can be attributed to male-biased sexual selection. Reduced purifying selection and increased sexual selection might indicate that dioecy indeed is an evolutionary dead end in Silene.

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