OREGON STATE UNIVERSITY

Project to extract DNA from extinct sea otters

02/04/2002

CORVALLIS - A project to extract DNA from the remains of animals that died hundreds, or even thousands of years ago has been awarded $10,802 in funding from Oregon Sea Grant.

Deborah Duffield and Virginia Butler, both professors at Portland State University, were notified this month that they had received the program development funds for their project, which seeks to extract and analyze the DNA from bones of sea otters found in ancient middens along the Oregon coast.

While the subject sounds sufficiently exotic to be a science fiction novel, the project is one part of an effort with a very serious goal: to reintroduce to the Oregon coast a species that was hunted to the edge of extinction during a 200-year span from the early 1700s to the 1900s.

The last Oregon sea otter was killed in 1906. The 1911 Fur Seal Treaty signed by Russia, Japan, Britain and the United States and a 1913 federal law in the United States effectively ended the harvest of the sea otter, but by that time the species was extinct in Oregon and Washington, and clinging to survival in California and Alaska.

An attempt to reintroduce sea otters in Oregon was launched in 1970, but was not successful. Thirty-one sea otters were taken from a site in Alaska and deposited on the Oregon coast near Port Orford. The next year 64 more were added to the population that survived the first year, but the colony did not last. Researchers from Oregon State University, including Ron Jameson, monitored the animals. According to Jameson, who retired from OSU in January, it was never clear exactly why the colony did not survive.

"It's one of those situations where we just don't have any evidence supporting any particular hypothesis. They produced pups, there was no huge immediate post release mortality. Suddenly, around 1975 or so, the numbers started to drop off and they effectively disappeared," he said.

Some of the animals may have moved north and joined the translocated colony in Washington, but it's difficult to say even that with any certainty, Jameson said.

"One of the things we did that was different than what we do today with translocated populations, we didn't have any kind of radio telemetry devices. Those animals weren't even tagged," he said.

"You can move sea otters to wherever you want, but they're going to choose where they want to stay," he said.

The effort to relocate sea otters to Washington's Olympic Peninsula bore better results; the otters survived and are now flourishing, growing from 59 in 1970 to more than 600 today.

In the intervening years, biologists and anthropologists argued whether the Alaska and California sea otter were the same species or genetically distinct cousins. In recent years, genetic studies support the idea that they are related but distinct subspecies. That being the case, supporters hope that finding which subspecies more closely resembles the extinct Oregon otters would result in a more successful attempt to reintroduce the animal to the state's coastal waters.

That is the aim of the project Duffield, a biologist at PSU, and Butler, an anthropologist, received funding for. Their research will focus on samples of sea otter bones and teeth found in Indian middens along the Oregon coast. The samples, mostly provided by Oregon State University anthropologist Roberta Hall, have been dated in a range from 200 to 2,000 years old.

"When there's been a coastal culture that has been using the sea otter as part of its food source and source of fur, there will often be good sized pieces of skeletal remains in the middens," Duffield said. "We have 18 really good ones, definitely sea otter."

Advances in DNA technology have made the work straightforward, if painstaking. "The technology for ancient DNA has just grown and grown in the last few years," Duffield said.

The researchers take a clean sample, "crack it or crush it," (in the case of this project the material will be frozen in liquid nitrogen and crushed,) then extract and purify the DNA.

Working with such old samples, it is difficult to extract complete DNA strands, Duffield said. But it is not necessary to have the entire sequence. Scientists can identify specific points of difference in the genes of existing California and Alaskan sea otters, and it is these markers that will be the focus of comparison with the DNA extracted from the long-dead Oregon samples.

PSU grad student Kim Valentine will perform the lab work.

Duffield agreed that the idea of extracting DNA from an extinct species smacked just a little of "Jurassic Park," the Michael Crichton novel in which DNA was extracted to allow the cloning of dinosaurs. But no one is talking about cloning the Oregon sea otter. Researchers just want to know which existing subspecies most closely resembles the extinct Oregon variety.

There is also one other important difference between science fiction and the real science she will be doing on the sea otter. "Luckily, they are much smaller" than Crichton's dinosaurs, she said with a laugh.