Negative global-scale association between genetic diversity and speciation rates in mammals

Genetic diversity is critical for species evolution and their adaptability to global changes, while speciation rate is critical for explaining large-scale patterns of species richness. Exploring correlates of variation in genetic diversity and speciation rates across species is a major interest of evolutionary biologists, but these two questions have mostly been investigated independently. Here, we assess the relationship between intra-specific genetic diversity and speciation rate for 1897 mammal species (~one third of the total diversity) covering all mammalian orders. We find a negative association between mitochondrial genetic diversity and speciation rate across mammalian clades globally. This association is not accounted for by differences in the ecological attributes of species. Our findings suggest a systematic link between micro- and macroevolutionary processes that need to be better understood and considered when investigating determinants of either genetic diversity or speciation rates.