Mitochondrial Genetic Diversity in the Crowned Sifaka (Propithecus coronatus) in a Fragmented Landscape
Résumé
Propithecus coronatus is an endangered, diurnal forest-dwelling lemur of northwestern Madagascar. We conducted the first extensive population genetic study for this species. We designed new primers to amplify and sequence the mitochondrial D-loop of 125 individuals from 14 localities in the northern part of the species’ distribution. Our aim was to assess the genetic variability and differentiation of this species in a fragmented landscape. Compared to other lemurs, crowned sifakas have a moderate level of haplotype diversity (0.853) and a low nucleotide diversity (1.21%). Despite the considerable forest fragmentation in the region surveyed, the species does not show strong signals of genetic structure as shown by the ΦST estimates, the network of haplotypes, and the limited correlation between genetic and geographic distance. The current mtDNA estimated effective population size was relatively large (median: 11,262; 95% HPD: 5,107−20,083), in agreement with recent census estimates, suggesting that a large number of individuals is still present across the species range. Using the Extended Bayesian Skyline Plot (EBSP) approach to reconstruct the demographic history of the species, we did not detect any genetic signal of change in population size. Despite the ongoing loss and fragmentation of their habitat, the population still harbors subtantial genetic diversity, likely as a partial consequence of a taboo against hunting the crowned sifaka among the Sakalava ethnic group inhabiting the area.