Ancient DNA determines treeshrew species
APRIL 2013 - Work has begun on research to test whether Southeast Asia’s treeshrews are more diverse than current taxonomy would suggest, thanks to the first National Science Foundation grant awarded to the University of Alaska Museum of the North for research conducted in its ancient DNA facility, the only lab of its kind in the State of Alaska.
The cover of the current issue of the Journal of Mammalogy features one such species that was "sunk" (placed in a previously described species or "synonymized") exactly 100 years ago. This poorly-studied group of mammals, once thought to be the closest living relatives to primates and still considered to be representative of ancestral primates, underwent a major bout of taxonomic synonymization in the latter half of the 20th century. That’s when over 120 described species or subspecies were categorized into the 20 species recognized today.
Mammalogy Curator Link Olson says this is one way our estimates of biodiversity can change--not because of discovery of new species or extinction of others, but because of taxonomic revisions made by biologists--often museum curators--based on existing museum specimens.
With funding from NSF and the National Geographic Society, Olson and several of his colleagues are trying to determine the actual number of treeshrew species using both DNA and morphological (anatomical, skeletal, histological, etc.) evidence.
“In this most recent article, we tested our own previous hypothesis based solely on DNA extracted from historic museum specimens up to 120 years old in the museum’s Ancient DNA Laboratory,” Olson said.
“We obtained morphological (in this case, skeletal) data by X-raying these same specimens to accurately measure the foot bones, which traditionally were left inside the study skin while the rest of the skeleton was discarded. We found congruence between the two types of data and were able to ‘resurrect’ three species from synonymy, including the one gracing the cover. This served as a test case, and we anticipate many more treeshrew species will be rescued from taxonomic oblivion in the near future.”
Olson says the scientists hope their work will aid conservation and management decisions in Southeast Asia, which is one of the world's hottest biodiversity hotspots and is undergoing rapid and accelerating rates of habitat destruction.
“In the case of treeshrews, we’re finding that species previously thought to be common and widespread across multiple landmasses are instead composed of many distinct species with, in some cases, very restricted distributions on single islands.”