Molecular Phylogenies of South American Mammals from "Palaeoproteomics"

Abstract

Proteomics, a technique with its origins in the late 1980s, has been increasingly applied to extinct faunal remains in recent years with the hopes that it will improve our understanding of the evolution of life on Earth. It has three obvious advantages over DNA methods: 1) several proteins, such as collagen, survive orders of magnitude longer (i.e., millions of years); 2) the methods are much easier to carry out and less prone to contamination; and 3) they are also much cheaper. Previously, proteomics analyses have been used to resolve the phylogenetic placement of an extinct mammal from Madagascar, the ‘Malagasy aardvark,’ which, following a century of debate, was given its own taxonomic order ‘Bibymalagasia.’ The collagen sequencing results obtained from proteomics placed it closest to the tenrecs and the grouping Tenrecoidea. Current research similarly applies these molecular methods to resolving the phylogenetic placement for several groups of South American mammals, including collagen sequencing results from endemic South American ungulates such as Toxodon (Notoungulata) and Macrauchenia (Litopterna) for which current phylogenetic placement on morphological criteria is still debated. We also make comparisons between results from various tissue types from other South American mammals of better understood phylogenies, including Megatherium and Hippidion to further explore the potential of proteomics techniques in the analysis of Late Quaternary faunal remains.