Francisco ÚBEDA DE TORRES On the origin of PRDM9-guided recombination hotspots
IBENS EEB External Seminar Series
12h
Le séminaire de Francisco Úbeda de Torres (School of Biological Sciences at Royal Holloway, University of London) aura lieu dans la salle Favard, IBENS 46 rue d’Ulm 75005 Paris
Across vertebrates, meiotic recombination is guided either by the protein PRDM9, which targets DNA sequences that are gradually destroyed, or by non-PRDM9 mechanisms that act in open chromatin without sequence specificity. Why a self-destructive mechanism evolves alongside a durable alternative remains unresolved. Using a population genetic model, we show that PRDM9-guided hotspots are generally disfavored because they generate fewer binding events and thus fewer crossovers needed to produce viable gametes. However, they can be favored when they promote simultaneous binding of both homologous chromosomes (symmetric binding), which more often produces crossovers. The evolutionary fate of PRDM9 thus reflects a trade-off between reduced binding and enhanced symmetric binding, explaining the diversity and evolutionary turnover of recombination mechanisms observed across vertebrates today.