Friday, 9 June 2017

Wolf evolution and 'settled science'

 June 9, 2017 by Ricki Lewis, Phd, Plos Blogs

Are the red and eastern wolves separate species, or hybrids with coyotes? And what has that got to do with climate change? Actually a lot, in illustrating what scientific inquiry is and what it isn't.

Comparing canid genomes
A report in this week's Science Advances questions conclusions of a 2016 comparison of genome sequences from 28 canids. The distinction between "species" and "hybrid" is of practical importance, because the Endangered Species Act circa 1973 doesn't recognize hybrids. But DNA information can refine species designations—or muddy the waters.

At first, genetic marker (SNP) studies hinted at a mixing and matching of genome segments among coyotes, wolves, and dogs. Then came full-fledged genome sequencing.

Last year Bridgett M. vonHoldt, head of Evolutionary Genomics and Ecological Epigenomics at Princeton and colleagues, scrutinized the 28 full genome sequences for signs of "lack of unique ancestry." They compared the genomes of 3 domestic dog breeds (boxer, German shepherd, and Basenji), 6 coyotes, a golden jackal from Kenya, and various wolves to 7 "reference" genomes from 4 Eurasian gray wolves (to minimize recent mutations) and 3 coyotes. The conclusion: lots of genes have flowed from coyotes and gray wolves into the genomes of the animals that became what we call red and eastern wolves, in different proportions.

A bit of background.
Red wolves were declared endangered in 1973. A dozen animals, selected by appearance and absence of coyote traits in their young, were "captively" bred to establish a population in North Carolina that is now several hundred strong. The 3 red wolf genomes evaluated in the 2016 study came from NC. Historically the animals are from the southeastern US.
Gray wolves and coyotes, according to the 2016 study, are "very close relatives with a recent common ancestry," although there's about as much genetic variability between the two species as within each.

Eastern wolves are from the Great Lakes and the Algonquin Park region of Ontario, moving eastward.

No comments:

Post a Comment

You only need to enter your comment once! Comments will appear once they have been moderated. This is so as to stop the would-be comedian who has been spamming the comments here with inane and often offensive remarks. You know who you are!

Related Posts with Thumbnails