The evolution of our diet has changed the dog genome

Unlike wolves, dogs have adapted to be able to feed on our leftovers. At least 7000 years ago, in parallel with the development of agriculture, dogs acquired the ability to digest starch. This was shown by Christophe HITTE and Laetitia LAGOUTTE, from the team of Catherine ANDRÉ, in collaboration with their colleagues of the École Normale Supérieure de Lyon and of the Museum National d’Histoire Naturelle. Published in Royal Society Open Science.

Dog skull and mandible (Bercy Neolithic site, Paris, c. 4000 BC). Photograph by J.-C. Domenech. Musée de l’Homme

Through the study of ancient specimens of European and Asian dogs, researchers from the IGDR helped discover that, contrary to their wolf ancestors, dogs gained the capacity to digest starch following the duplication of the Amy2B gene, at least 7000 years ago. Amy2B encodes an amylase enzyme that catalyses the hydrolysis of starch. Duplication of this gene coincides with an ancient stage of agriculture development and reflects an adaptation to nutritional change. Published in Royal Society Open Science, the study demonstrates an example of coevolution and highlights the influence of human culture on the genome of the first dogs.

Canine and Human coevolution

Not only did agriculture revolutionise human society, it also contributed to transforming the genome of our oldest friends: dogs. Through DNA analysis of archaeological remains, this new study reveals that domesticated dogs whose genome underwent duplication of the Amy2B gene were naturally selected, because they were better able to digest starch. This adaptation allowed them to live alongside humans as our world was changing.

Genetic evolution of dogs is parallel to that of humans: the emergence of agriculture led to an increase in the amount of starch in the human diet, and dogs, being their first domesticated friends, had to adapt. In fact, the copy number of the same amylase gene also increased in the human genome during this period.

The discoveries that initiated this study were made three years ago when scientists from the University of Uppsala, Sweden, showed that modern dogs have between four and 34 copies of the Amy2B gene, whereas wolves typically have only two copies. In this new study, scientists determined the period of time in which this change occurred. They extracted genetic material from bones and teeth of 88 dog specimens from several Eurasian archaeological sites. Through ancient DNA analysis, the researchers were able to obtain results from 13 samples.

Reference

Amy2B copy number variation reveals starch diet adaptations in ancient European dogs.
Morgane Ollivier, Anne Tresset, Fabiola Bastian, Laetitia Lagoutte, Erik Axelsson, Maja-Louise Arendt, Adrian Bălăşescu, Marjan Marshour, Mikhail V. Sablin, Laure Salanova, Jean-Denis Vigne, Christophe Hitte, Catherine Hänni.
Royal Society open science 2016 3 160449; DOI: 10.1098/rsos.160449. Published 9 November 2016

More information

Original scientific article

Article published in French on the University of Rennes 1’s web site on November 22, 2016 - Traducted in english by Xavier PINSON and Sarah DIXON

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