Comment on “Whole-genome sequence analysis shows two endemic species of North American wolf are admixtures of the coyote and gray wolf”

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Science Advances  07 Jun 2017:
Vol. 3, no. 6, e1602250
DOI: 10.1126/sciadv.1602250
  • Canis
  • admixture
  • hybridization
  • whole-genome sequencing
  • species conservation
  • wolves
  • coyotes


In a recent article, vonHoldt and colleagues (1) use whole-genome sequence data to address the relationships and evolutionary origins of several North American canid taxa. The authors conclude that two taxa, the red wolf (Canis rufus) and the eastern wolf (Canis lycaon), are not long-diverged lineages as other researchers have concluded from genetic (27) and fossil evidence (8, 9) but are, rather, populations resulting from recent admixture between gray wolves (Canis lupus) and coyotes (Canis latrans). They use this conclusion to argue that endangered species policy should better account for hybridization and admixture. We agree that hybridization and admixture are widespread in the natural world and that the conservation policy needs to be updated to account for this biological reality. However, we strongly disagree with their conclusion that red and eastern wolves are of recent hybrid origin and we conclude that their analysis does not actually test the hypothesis of a recent hybrid origin. Their data are consistent with multiple hypotheses for the origins of red and eastern wolves, including relatively old origins of these taxa. Furthermore, we argue that their data do not support “a lack of unique ancestry in red and eastern wolves” (1); rather, substantial evidence still supports the conclusion that red and eastern wolves represent genetically distinct taxa among North American canids. Below, we detail this perspective and argue for further analyses that would directly test competing hypotheses for the evolutionary origins of these groups.


Analysis of whole-genome sequence data necessarily relies on a relatively small number of individual samples that are taken to be representative of larger populations or taxa. In this case, the choice of representative samples is problematic in several respects. First, of the three individuals chosen as representative nonadmixed coyotes, …

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