DNA analysis of ancient dogs of the Americas: Identifying possible founding haplotypes and reconstructing population histories

doi:10.1016/j.jhevol.2014.10.012

Abstract

As dogs have traveled with humans to every continent, they can potentially serve as an excellent proxy when studying human migration history. Past genetic studies into the origins of Native American dogs have used portions of the hypervariable region (HVR) of mitochondrial DNA (mtDNA) to indicate that prior to European contact the dogs of Native Americans originated in Eurasia. In this study, we summarize past DNA studies of both humans and dogs to discuss their population histories in the Americas. We then sequenced a portion of the mtDNA HVR of 42 pre-Columbian dogs from three sites located in Illinois, coastal British Columbia, and Colorado, and identify four novel dog mtDNA haplotypes. Next, we analyzed a dataset comprised of all available ancient dog sequences from the Americas to infer the pre-Columbian population history of dogs in the Americas. Interestingly, we found low levels of genetic diversity for some populations consistent with the possibility of deliberate breeding practices. Furthermore, we identified multiple putative founding haplotypes in addition to dog haplotypes that closely resemble those of wolves, suggesting admixture with North American wolves or perhaps a second domestication of canids in the Americas. Notably, initial effective population size estimates suggest at least 1000 female dogs likely existed in the Americas at the time of the first known canid burial, and that population size increased gradually over time before stabilizing roughly 1200 years before present.

Keywords

Ancient DNA;
Domestication;
Population genetics;
Canis lupus familiaris;
Mitochondrial DNA;
New World

Introduction

The domestic dog (Canis lupus familiaris) holds a unique place in the history of animal domestication, in that this species was not only the first to be domesticated, but was also domesticated for a variety of purposes: as guards, hunting aids, and even as companions ( Clutton-Brock, 1995). Dog remains dating to 10,000–14,000 years before present (BP) have been discovered across Eurasia, and genetic studies suggest that dogs were domesticated from gray wolves between 11,000 and 20,000 years ago ( Germonpré et al., 2009, Pang et al., 2009, Ding et al., 2012 and Freedman et al., 2014). Recent analysis of an ancient Siberian canid with a morphology suggestive of a ‘transitional dog’ and a mitochondrial DNA (mtDNA) haplotype found in contemporary dog populations suggests that domestication could have taken place in excess of 33,000 years BP ( Druzhkova et al., 2013). The exact origin of domestic dogs is uncertain, though suggested geographic origins include the Middle East, Southeast Asia, and Europe ( Pang et al., 2009, Vonholdt et al., 2010, Ardalan et al., 2011, Ding et al., 2012 and Thalmann et al., 2013). Most recently, however, results suggest that modern wolf populations diverged from one another at around the same time as dog domestication, and therefore modern populations cannot be used to determine where dogs were first domesticated ( Freedman et al., 2014).

Dogs are found in a variety of archaeological contexts in the Americas that date as early as 10,500 years BP, with the first unequivocal dog burial dating to roughly 9000 years BP (Morey and Wiant, 1992). Interestingly, genetic analysis of ancient dog mtDNA indicates that many of these dogs were domesticated from Eurasian wolves, suggesting that these ancient dogs likely came to the Americas with humans (Leonard et al., 2002). However, some ancient dogs in the Americas have mitochondrial haplotypes either shared with or nearly identical to those of North American wolves, suggesting either post-domestication admixture between dogs and wolves or even a separate domestication of canids in the Americas (Koop et al., 2000 and Van Asch et al., 2013). Ethnohistorical records indicate that Native American peoples used dogs as hunters, herders, haulers, sources of food, and companions, and this practice likely spans into prehistory (Schwartz, 1997).

Cheryl & ethnovet

twitter

Friday, 17 April 2015