Résumé
Marine connectivity measurement can be improved by studying the spatial decay of DNA fragments that are identical by descent (IBD). This information can be used to assess local variation in intragenerational dispersal distance across the landscape. The size of IBD fragments depends on the speed at which recombination erodes them through the time. Recombination rates vary along the genome, and therefore this variation must be taken into account for understanding the temporal dynamics of IBD fragment size reduction. Consequently, measuring recombination rate variation along the genome is a necessary prerequisite to estimate dispersal distances from IBD segments. Recombination rates can be estimated using genome resequencing population genetic data, using a sample size of only a few dozen of individuals. After reconstruction of the haplotypic phase, population inference methods based on linkage disequilibrium (LD) can be used to infer the population-scaled recombination rate parameter, ⍴=4Ner. These methods produce estimates of the historical recombination rates of a population, and are very convenient to study non-model species for which laboratory crosses are difficult or impossible. These LD-based approaches should thus make it possible to use IBD fragments to improve connectivity studies in marine ecosystems.