An MU study sorts out the details of black bears' genetic past.
There are three bears on Missouri’s official state seal, three more than — because of hunting and habitat loss — may have actually existed in the state by the 1950s. A decade or so later, thanks in part to a repopulation project originating in Arkansas, a handful of Ursus americanus began to make grudging progress toward repopulating their ancestral homes.
Today bear populations in Arkansas, Missouri and Oklahoma are much improved. And now, thanks to a new genetic mapping project led by MU’s Emily Puckett, a recent doctoral graduate in biological sciences, these bears are among those in a position to help more of their species survive.
Using advanced nuclear genomics, Puckett says, she and her team were able to describe three geographic lineages of bears in areas of North America and in Alaska. After identifying these lineages, the team further delineated them into nine geographically relevant regional clusters. This yielded a number of insights, among them that black bears in Alaska, surprisingly, are more closely related to bears in the eastern regions of the U.S. and Canada than those located in the west. The study also charted the ancient movement patterns of black bears, and provided detailed “genetic maps” that conservation management officials can use to maintain healthy bear populations.
“What’s exciting about the results of this study is that we now understand how bears are related across different geographical ranges and we can utilize this information to begin understanding functional adaptations such as hibernation characteristics,” Puckett says.
The most prevalent method used in studying the distribution of genetic lineages across a species range is to tap into the mitochondrial DNA of the cell, which mammals inherit only from their mother. Using more advanced techniques, Puckett and her team, including Lori Eggert, an associate professor of biological sciences whose work with elephants was featured in Illumination’s Fall/Winter 2011 issue, analyzed the nuclear genome that carries vastly more genes and information about a species.
The team received more than 500 black bear DNA samples from wildlife agencies, universities and other private partners.
“With the information gleaned from nuclear genomics, scientists are able to put a finer point on inheritance and lineages,” Puckett said. “By doing so, we were able to trace lineages through black bears in these geographically diverse regions and through maternal and paternal lines showing evolution. As we began pinpointing these findings, it led to exceptional maps of genetic clusters we’d not previously seen and even ancient migration patterns of black bears.”
The study was published in May in the journal, Molecular Biology and Evolution.