Genome diversity and species richness in mammals

Evolutionary changes in karyotype have long been implicated in speciation events; however, the phylogenetic relationship between karyotype diversity and species richness in closely and distantly related mammalian lineages remains to be fully elucidated. Here we examine the association between genome diversity and species diversity across the class Mammalia. We tested five different metrics of genome diversity: clade-average genome size, standard deviation of genome size, diploid and fundamental numbers (karyotype diversity), sub-chromosomal rearrangements and percent synteny block conservation. We found a significant association between species richness (phylogenetic clade diversity) and genome diversity at both order and family level clades. Karyotype diversity provided the strongest support for a relationship between genome diversity and species diversity. Our results suggest that lineage specific variations in genome and karyotype stability can account for different levels of species diversity in mammals.