Relaxation of selective constraint on dog mitochondrial DNA following domestication

Abstract

The domestication of dogs caused a dramatic change in their way of life compared with that of their ancestor, the gray wolf. We hypothesize that this new life style changed the selective forces that acted upon the species, which in turn had an effect on the dog’s genome. We sequenced the complete mitochondrial DNA genome in 14 dogs, six wolves, and three coyotes. Here we show that dogs have accumulated nonsynonymous changes in mitochondrial genes at a faster rate than wolves, leading to elevated levels of variation in their proteins. This suggests that a major consequence of domestication in dogs was a general relaxation of selective constraint on their mitochondrial genome. If this change also affected other parts of the dog genome, it could have facilitated the generation of novel functional genetic diversity. This diversity could thus have contributed raw material upon which artificial selection has shaped modern breeds and may therefore be an important source of the extreme phenotypic variation present in modern-day dogs.

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 length, base composition and codon distribution of the COI gene in the Tibetan Mastiff, German Shepherd and Borzoi were consistent with those in other Canidae species (Bjö rnerfeldt et al, 2006).…”

Complex population structure in African village dogs and its implications for inferring dog domestication history

“…Like other domesticated animals (e.g., cats, horses, and pigeons), dogs consist of breeds intensely selected for specific traits and feral populations that have been left to adapt to local conditions with ''random'' breeding. Dense genotyping and resequencing in these species should reveal genes underlying domestication in random-bred populations, instead of just those that have been under strong artificial selection in breed animals, and whether the relaxation of selective constraint observed in these species (19) is a product of recent breeding practices or domestication per se. Resequencing in indigenous village dogs will also be necessary to obtain markers free of ascertainment bias to estimate the amount of genetic variation in dogs that is absent in existing modern breeds, and the degree to which present-day indigenous village dogs represent populations that have been randomly breeding since dog domestication versus remnants of ancient, indigenous breeds.…”

Evaluation of the effectiveness of introducing new alleles into the gene pool of a rare dog breed: Polish Hound as the example

“…The sequences of the Polish Hounds were compared to 67 sequences found in 55 dog breeds representing different types and different FCI groups which were deposited in GenBank under accession numbers EU408245-408307 (Webb and Allard, 2009) and DQ4804489-480502 (Björnerfeldt et al, 2006). Phylogenetic analysis of the mtDNA haplotypes was performed using MEGA v4.0 software (Tamura et al, 2007).…”