title: Diet adaptation in dog reflects spread of prehistoric agriculture.
abstract: Adaptations allowing dogs to thrive on a diet rich in starch, including a significant AMY2B copy number gain, constituted a crucial step in the evolution of the dog from the wolf. It is however not clear whether this change was associated with the initial domestication, or represents a secondary shift related to the subsequent development of agriculture. Previous efforts to study this process were based on geographically limited data sets and low-resolution methods, and it is therefore not known to what extent the diet adaptations are universal among dogs and whether there are regional differences associated with alternative human subsistence strategies. Here we use droplet PCR to investigate worldwide AMY2B copy number diversity among indigenous as well as breed dogs and wolves to elucidate how a change in dog diet was associated with the domestication process and subsequent shifts in human subsistence. We find that AMY2B copy numbers are bimodally distributed with high copy numbers (median 2nAMY2B=11) in a majority of dogs but no, or few, duplications (median 2nAMY2B=3) in a small group of dogs originating mostly in Australia and the Arctic. We show that this pattern correlates geographically to the spread of prehistoric agriculture and conclude that the diet change may not have been associated with initial domestication but rather the subsequent development and spread of agriculture to most, but not all regions of the globe.
authors.affiliation: Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Arendt
authors.affiliation: School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: K M
authors.initials: KM
authors.lastname: Cairns
authors.affiliation: School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: J W O
authors.initials: JW
authors.lastname: Ballard
authors.affiliation: Science for Life Laboratory, School of Biotechnology, Royal Institute of Technology (KTH), Solna, Sweden.
authors.forename: P
authors.identifier: 0000-0002-1495-8338
authors.initials: P
authors.lastname: Savolainen
authors.affiliation: Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Axelsson
mesh_terms: D000222:Adaptation, Physiological; D000383:Agriculture; D000818:Animals; D000829:Animals, Domestic; D001110:Arctic Regions; D001315:Australia; D001947:Breeding; D046028:Canidae / Q000235:genetics; D056915:DNA Copy Number Variations; D004032:Diet; D004285:Dogs / Q000235:genetics* / Q000502:physiology; D000071278:Domestication; D055292:Pancreatic alpha-Amylases / Q000235:genetics*; D013213:Starch
chemical_list: D013213:Starch; D055292:Pancreatic alpha-Amylases