Abstract
BackgroundDomesticated from gray wolves between 10 and 40 kya in Eurasia, dogs display a vast array of phenotypes that differ from their ancestors, yet mirror other domesticated animal species, a phenomenon known as the domestication syndrome. Here, we use signatures persisting in dog genomes to identify genes and pathways possibly altered by the selective pressures of domestication.ResultsWhole-genome SNP analyses of 43 globally distributed village dogs and 10 wolves differentiated signatures resulting from domestication rather than breed formation. We identified 246 candidate domestication regions containing 10.8 Mb of genome sequence and 429 genes. The regions share haplotypes with ancient dogs, suggesting that the detected signals are not the result of recent selection. Gene enrichments highlight numerous genes linked to neural crest and central nervous system development as well as neurological function. Read depth analysis suggests that copy number variation played a minor role in dog domestication.ConclusionsOur results identify genes that act early in embryogenesis and can confer phenotypes distinguishing domesticated dogs from wolves, such as tameness, smaller jaws, floppy ears, and diminished craniofacial development as the targets of selection during domestication. These differences reflect the phenotypes of the domestication syndrome, which can be explained by alterations in the migration or activity of neural crest cells during development. We propose that initial selection during early dog domestication was for behavior, a trait influenced by genes which act in the neural crest, which secondarily gave rise to the phenotypes of modern dogs.
Highlights
Domesticated from gray wolves between 10 and 40 kya in Eurasia, dogs display a vast array of phenotypes that differ from their ancestors, yet mirror other domesticated animal species, a phenomenon known as the domestication syndrome
Use of village dogs eliminates bias in domestication scans associated with breed formation Comparison using FST outlier approaches Utilizing pooled FST calculations in sliding windows along the genome, two previous studies [5, 8] isolated candidate domestication regions from sample sets consisting of mostly breed dogs and wolves
In order to demonstrate the impact of sample choice on the detection of selective signatures associated with early domestication pressures, rather than breed formation, we adapted the methods from these studies and identified outlier loci empirically [5, 8]
Summary
Domesticated from gray wolves between 10 and 40 kya in Eurasia, dogs display a vast array of phenotypes that differ from their ancestors, yet mirror other domesticated animal species, a phenomenon known as the domestication syndrome. Pendleton et al BMC Biology (2018) 16:64 animal taxa [5,6,7,8,9,10,11, 17], and several genes are highlighted as likely associated with the domestication syndrome This is not unexpected given that more than a dozen diverse behavioral and complex physical traits fall under the syndrome, making it likely that numerous genes with pleiotropic effects contribute through mechanisms which act early in organismal development [18, 19]. For this reason, the putative role of the neural crest in domestication has gained traction [18, 20, 21]. The adrenal and pituitary systems, which are derived from neural crest cells, influence aggression and the “fight or flight” behavioral reactions, two responses which are lessened in domesticates [22]
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