What can chromosomes tell us about the origins of primates?

Our study investigated the usefulness of chromosome painting data in analysing phylogenetic affinities among the orders included in Euarchontoglires (Primates, Rodentia, Scandentia, Lagomorpha and Dermoptera). We applied Maximum Parsimony and Baysian inference in the comparison of karyotypic similarities and differences visualised among 41 Euarchontaglires species and one monotreme outgroup. In total, 161 characters were identified on the basis of presence/absence of human orthologous segmental associations. The inclusion of this large sample covering a wide phylogenetic spectrum revealed that some syntenies previously reported as synapomorphic are in fact homoplastic traits. The high levels of homoplasy reflected in our data suggest that the same associations occur repeatedly. Karyotype evolution is relatively rapid, making it more informative about shallow rather than deep divergences.