04 March 2013
The evolutionary relationship between horses and their extinct and closest living relatives
Researchers from CGG have characterized the full mitochondrial genome variation of all contemporary equids as well as three extinct species: the Sussemione, New World stilt-legged horse, and the quagga. This information significantly advanced our knowledge regarding equid phylogenetic relationships, in particular about the very rapid succession of speciation events that gave rise to the present diversity of this iconic group of mammals.
Contemporary equids consist of the diversity of horses, donkeys and zebras that we know today. However, the diversity of this group of monodactyl mammals used to be considerably richer in the past.
A controversial history
A long history of over 55 million years is indeed documented in the fossil record, showing drastic changes in body size and morphology over time and providing some of the most famous textbook examples of evolution-in-action.
Despite this, many aspects of the evolutionary history of equids are still controversial. For example how the different extant species are related to each other, and also to a series of recently extinct species, is a matter of scientific debate.
Linking past and present biodiversity
The survival of traces of DNA in fossils makes it possible to retrieve genetic information from extinct animals and identify which living species they are most closely related to, providing a unique opportunity to link past and present biodiversity.
This is exactly what Vilstrup and colleagues have done recently in a paper published in PLoS ONE.