Multiple and Ancient Origins of the Domestic Dog

Abstract

Mitochondrial DNA control region sequences were analyzed from 162 wolves at 27 localities worldwide and from 140 domestic dogs representing 67 breeds. Sequences from both dogs and wolves showed considerable diversity and supported the hypothesis that wolves were the ancestors of dogs. Most dog sequences belonged to a divergent monophyletic clade sharing no sequences with wolves. The sequence divergence within this clade suggested that dogs originated more than 100,000 years before the present. Associations of dog haplotypes with other wolf lineages indicated episodes of admixture between wolves and dogs. Repeated genetic exchange between dog and wolf populations may have been an important source of variation for artificial selection.

The origin of the Tibetan Mastiff and species identification of Canis based on mitochondrial cytochrome c oxidase subunit I (COI) gene and COI barcoding

“…The phylogenetic trees (Figure 2b) and haplotype network (Figure 3b) of the Tibetan Mastiff and domestic dogs constructed on the basis of COI barcoding were consistent with the COI gene. According to the NJ tree and network constructed by the COI gene sequence, we found 23 haplotypes clustered into four clades; the numbers of haplotypes (17, 73.91%) and individuals (66, 64.71%) of Clade A were more than those of Clades B and C, which is consistent with previous reports (Vilà et al, 1997;Savolainen et al, 2002). These results support the view of the East Asian origin of domestic dogs and the Clade A origin of the Tibetan Mastiff, which are consistent with the results according to the complete sequence of the mitochondrial genome (Li et al, 2011).…”

“…A total of 23 haplotypes were defined in the COI gene sequence of the Tibetan Mastiff and 76 domestic dog breeds (Table 1), and the haplotype percentage was 21.50%. The polymorphism was lower than that based on the mitochondrial displacement loop (D-loop; especially hypervariable region 1; Vilà et al, 1997;Savolainen et al, 2002;Luo, 2003), but higher than that based on the mitochondrial Cytb gene (Li et al, 2008). Vilà et al (1997) found 27 variable sites and identified 26 haplotypes in the 261-bp D-loop region with a 10.34% polymorphism loci percentage and an 18.57% haplotype percentage.…”

“…The polymorphism was lower than that based on the mitochondrial displacement loop (D-loop; especially hypervariable region 1; Vilà et al, 1997;Savolainen et al, 2002;Luo, 2003), but higher than that based on the mitochondrial Cytb gene (Li et al, 2008). Vilà et al (1997) found 27 variable sites and identified 26 haplotypes in the 261-bp D-loop region with a 10.34% polymorphism loci percentage and an 18.57% haplotype percentage. Savolainen et al (2002) found 128 variable loci and identified 109 haplotypes in the 582-bp D-loop region with a 21.84% polymorphism loci percentage and a 16.67% haplotype percentage.…”

“…All sequences of domestic dogs are primarily clustered in four clades, considering that the domestic breed dogs had four maternal origins. Vilà et al (1997) found that Clades A, B, C and D contained 19, 1, 3 and 3 haplotypes, respectively, among 26 haplotypes. The earliest domestication is estimated at about 100 000 years before the present (YBP) and originated in Europe, Southwest Asia and East Asia, considering its multiregion and asynchronous domestic events.…”

Finding cardiovascular disease genes in the dog

“…Thus, selection of a particular breed for a mapping study over other available breeds could dramatically reduce the work load and expense associated with the study, and judicious selection of breeds for studies of shared disorders becomes very important. Finally, this study demonstrated that haplotypes or blocks of alleles are frequently shared between dog breeds, a result that was not surprising given the recent evolution of the dog from the wolf 73,74 . This means that a single map and a single SNP chip will be useful for mapping studies in any breed of dog.…”