CONICET | Buscador de Institutos y Recursos Humanos

Accordingto modern evolutionary theory, changes occurring at the genetic, population,and biodiversity (formation of new species) levels are the result of a common evolutionaryprocess. Consequently, it is expected that the rates at which these changesoccur are coupled. In fact, a positive correlation between molecular evolutionand diversification rates has been observed in some clades at broadphylogenetic scales. However, whether this is a common feature ofmacroevolutionary diversification is currently unknown.Here,we studied the fine-scale (i.e. lineage level) phylogenetic association betweendiversification and molecular rates across the Primate radiation, a largemammalian order with more than 400 species. We estimated per-branchsubstitution rates using fossil calibrations for nuclear and mitochondrialalignments with a total length of ~60.000bp for 367 species. Additionally, weestimated per-branch speciation rates using a recently developed phylogeneticdiversification model (ClaDS). Phylogenetic correlations among per-branchestimates of molecular and speciation rates revealed a complex pattern ofassociations. Intriguingly, while mitochondrial substitution rates showed a positivecorrelation with speciation, correlations were negative for nuclear rates.Moreover, within the mitochondrial alignment, the association with speciationwas stronger in less neutral partitions (1st and 2ndcodon positions and mtRNA) than in a more neutral one (3rd codonposition). We propose possible mechanisms, involving the interplay betweendemographic and life history factors, that might help explain these contrastingpatterns of associations between the diversification and molecular evolutionrates. These results have interesting implications for understanding macroevolutionarydiversification processes.

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