Grizzly bear DNA database grows by the day

This summer, grizzly bears have been confirmed in the Big Hole River Valley of Montana for the first time in the last 100 years.

Montana Fish, Wildlife and Parks bear manager Kevin Frey said they do have hair samples from at least one grizzly from earlier this summer in the Big Hole and the state plans on having the samples analyzed to find out if biologists can track the origins of the bear.

The case is just another illustration of how far DNA analysis of bears has come in the past 25 years.

Tracking of grizzly bears through DNA analysis started in the 1990s in British Columbia. After years of research both in the U.S. and Canada, the database of individual bears in various ecosystems from Banff National Park in Canada to Yellowstone numbers about 5,000, said David Paetkau, president of Wildlife Genetics International.

Paetkau’s firm has done the genetic analysis of grizzly bear DNA since the infancy of grizzly bear research. Paetkau explained in a recent interview that DNA is stored in databases by ecosystem, and each ecosystem and the agencies that pay for the sampling, own their own data.

But if a further analysis of a bear is needed, his firm can cross-reference the DNA to the other databases in an effort trace the bear’s lineage. If time is of the essence, for example if a bear is in a trap and biologists need to know about it quickly, he said the company can analyze a sample in just a few hours.

“We often can get results in the same day,” he said.

Using DNA in wildlife research has only come about in the past 25 years or so. Technological breakthroughs made the research far more practical, he explained. One was polymerase chain reaction — a fast and inexpensive technique used to “amplify” — copy — small segments of DNA. The technique was created by Nobel-prize chemist Kary B. Mullis. In bear research, it reduces the amount of tissue that’s needed for analysis by several million, Paetkau noted.

That’s an important aspect when working with something like grizzly bear hair. The DNA analysis isn’t done from the hair, it’s done from the hair follicle, the tiny bits of skin at the end of the hair.

Advances in genome marking have also made the task far easier, he noted.

The first DNA studies of bears by capturing only their hair were done by John G. Woods in Canada back in the late 1990s. His paper “Genetic Tagging of Free Ranging Black and Brown Bears” was the first in the field.

Other studies followed Woods, but Kate Kendall’s work across the Northern Continental Divide Ecosystem — an 8-million plus acre swath of land that includes all of Glacier National Park and the Bob Marshall Wilderness and surrounding wildlands was the largest.

That study looked at both natural bear rubs — where bears rub on trees or in some cases, fenceposts — and in hair traps, where bears were lured into barbed wire “traps” to a lure station.

When the bear went to smell the lure, they would leave hair on a four-barbed wire fence.

All told, Kendall’s study gathered about 34,000 hair samples and ultimately identified 545 individual grizzlies.

Paetkau’s lab did all the work.

“We bought a 7,000 square foot warehouse,” to handle the extra work, he recalled,.

Today, gathering bear hair is an established way to track bears. Kendall is currently working on a paper that looks at the efficacy of monitoring bear populations solely through rub trees, she said last week.

Rub tree data has the advantage over other methods because it doesn’t require actually capturing a bear. It’s non-invasive and easier on the bears. Currently, population trend studies require capturing and collaring bears and then tracking them to see how long they live and what offspring they produce.

DNA also allows scientists to look at the bear family trees. U.S. Geological Scientist Tabitha Graves is working on research to create a grizzly bear family tree.

From Frey’s perspective, the fact that grizzlies are dispersing in places they haven’t been in centuries is an indication the species is doing well.

“The population must be doing pretty good if they’re showing this much expansion,” he noted.