Back in September, I was lucky enough to get a few photos of a coyote that was spotted in a hayfield east of here. I was therefore quite interested in an interview I heard recently on Bob McDonald’s Quirks and Quarks on CBC Radio on October 3rd. Bob was speaking with Dr. Roland Kays, Curator of Mammals at the New York State Museum about Kays’ research on eastern coyotes. His paper, Rapid adaptive evolution of northeastern coyotes via hybridization with wolves, co-authored with Abigail Curtis and Jeremy Kirchman, appears in Biology Letters.
Coyotes (Canis latrans) are a western species. It wasn’t until 1920 that the first coyotes began to make their way into Ontario. Coyotes expanded their eastern range on two fronts, with one set travelling east from Minnesota via a route north of the Great Lakes into Ontario, while a second front continued east south of the Great Lakes. Kays and his partners studied the mtDNA from 686 eastern coyotes and measured 196 skulls. They found evidence that coyotes on the northern front hybridized with wolves as their expansion brought them into contact with their larger relatives, while the coyotes of the southern front did not. The hybrid northern coyotes found in Ontario are larger in size, have larger skulls and exhibit greater sexual dimorphism (a wolf trait) than is found in the non-hybrid coyotes that moved into New York and Pennsylvania
They suggest that hybridization allowed the northern coyotes to better exploit the niche left vacant by extirpated wolves. The larger skulls of these coyotes allowed them to better take advantage of the booming deer population, resulting in a colonization rate 5 times more rapid than that experienced by coyotes to the south. Hybridization is thus a conduit by which the genetic variation of an extirpated species, the wolf, has contributed to the success of a recently-arrived species and by which wolf genetics have been reintroduced into their former range.
You can listen to the interview on this Quirks & Quarks podcast. The coyote segment begins at the 42:40 minute point.
That’s interesting. It once again blurs the lines of what we perceive as species.
mtDNA is mitochondrial DNA. The mitochondria are sort of like “organs” inside your cells that are responsible for producing the molecular units of energy that your body uses to do anything. They have their own DNA, separate from that found in the nucleus of the cell. Because the sperm is just a packet of DNA and not really a cell proper, all of your mtDNA comes from your mother, and is a clone of hers. Aside from a little bit of mutation along the way, it is passed down nearly intact from generation to generation, through the female line.
I’m sort of curious about how they used this to trace wolf contributions, since as soon as there was a female coyote as the mother, the wolf mtDNA would in theory be lost. I suppose, though, that if there was the presence of wolf mtDNA among the northern population and it was absent in the southern population you could pretty easily make the conclusion that there had been some hybridization, even if you couldn’t conclusively tell if coyote-mtDNA individuals were hybrids or not.
I can’t speak to the issue you raise about mtDNA. If you try the links to the article and podcast, you many find some clarification. Or just google Roland Kays, …or you could probably email him at the museum! Apparently Ontario coyotes are, on average, 10 lbs larger than western or New York coyotes, being 40-50 lb rather than 30-40 lb. McDonald queried whether they might qualify as a new species, but Kays says that is premature.
[…] spread through the north met and hybridized with wolves, thus acquiring some of their traits. (See this post at my mom’s blog for more about the research examining the two populations.) Larger bodies […]
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