University of Kentucky College of Agriculture, Food & Environment

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Gluck Center > News > Seminar Announcement

— Auditorium, Room 110 — Gluck Equine Research Center

Thursday, January 8, 2015 — 4:00 pm

Illuminating the Last 4 Million Years of Equine Evolution.

Ludovic Orlando, PhD

Associate Professor, Centre for GeoGenetics
Natural History Museum of Denmark
Øster Voldgade 5-7, 1350K Copenhagen
Denmark

Horses, zebras, and asses represent the only living members of the equid family. This family originated in Northern America some 55 million years ago and flourished into a large number of species during the Tertiary period. The deep evolutionary history of equids is well documented in the paleontological record and represents a textbook example of evolution. However, their recent evolutionary history remains largely unknown. By sequencing the genome of a 700,000 year-old horse, representing the oldest genome hitherto sequenced, our group has shown that the most recent common ancestor of extant equids lived some 4 million years ago. Further genome sequencing for each species within the family illuminated the patterns and processes of the equine radiation, from its early split in the New World to its subsequent migrations into Eurasia and Africa. This revealed large-scale demographic expansions and contractions following major climatic changes as well as the genetic toolkit that underlies the species’ adaptations. Importantly, our comparative genome dataset revealed multiple cases of gene flow between species. This shows that the species barrier is not always waterproof, and challenges current speciation models, which assume that changes in the chromosomal structure often result in full reproductive isolation. In addition to help better comprehend the processes driving the origins of species and their adaptation, the equid family, which includes not less than two domesticated species, also offers a fantastic opportunity to study how humans transformed wild animals into domesticates that best suit their purpose. Using ancient DNA, our group reconstructed the complete genomes from horses that lived prior to the domestication and identified 125 genes that have been positively selected since. This conservative set of genes reveals the range of physical, physiological and behavioral functions that have been reshaped by humans during history and antiquity.

References:

1) Schubert M, et al. 2014. Prehistoric genomes reveal the genetic foundation and cost of horse domestication. PNAS in press.

2) Orlando L, et al. 2013. Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse. Nature 499:74-8.

Veterinarians seeking Continuing Education credits must sign the CE book and request their CE certificate at the time of the seminar.

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Maxwell H.Gluck Equine Research Center
Department of Veterinary Science, University of Kentucky
Lexington, Kentucky 40546-0099

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