Unequal contribution of sexes in the origin of dog breeds
Anna-Karin Sundqvist 1, Susanne Björnerfeldt 1, Jennifer Leonard 1, Frank Hailer 1, Åke Hedhammar 2, Hans Ellegren 1 and Carles Vilà 1*
1 Uppsala University
2 Swedish University of Agricultural Sciences
* To whom correspondence should be addressed. E-mail: carles.vila{at}ebc.uu.se.
Submitted on February 22, 2005
Revised on September 29, 2005
Accepted on 29 September 2005
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Abstract |
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Dogs (Canis familiaris) were domesticated from the gray wolf (Canis lupus) at least 14,000 years ago, and there is evidence of modern-like breeds 4000 years ago. However, recent genetic analyses have suggested that modern dog breeds have a much more recent origin, probably less than 200 years ago. To study the origin of contemporaneous breeds we combined the analysis of paternally inherited Y chromosome markers with maternally inherited mitochondrial DNA and biparentally inherited autosomal microsatellite markers in both domestic dogs and their wild ancestor, the gray wolf. Our results show a sex bias in the origin of breeds, with fewer males than females genetically contributing, which clearly differs from the breeding patterns in wild gray wolf populations where both sexes have a similar contribution. Furthermore, a comparison of mitochondrial DNA and Y chromosome diversity in dog groups recognized by the World Canine Organization shows that paternal lineages are more differentiated among groups than maternal lineages. This indicates greater exchange of males than of females between breeds with similar morphology and/or behavior (breeds from the same group).
Key Words:
Y chromosome, domestication, gray wolf, mtDNA, purebred dogs
