Scientists decode painted turtle's DNA
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VANCOUVER - Scientists have decoded the DNA of the Western painted turtle, and hope that unravelling the mystery of the reptiles may lead to medical breakthroughs for humans.
They are the most abundant turtle in North America, with a northernmost range from Ontario west to British Columbia, where they are listed as endangered on the Pacific Coast and of special concern in the rest of the province.
The shelled reptile, named for the bright yellow and red stripes that adorn its body, is a fresh water species that can freeze solid and return to life when thawed.
It can also hold its breath for up to four days at room temperature without suffering oxygen deprivation and up to four months when hibernating, said Brad Shaffer of UCLA's Institute of the Environment and Sustainability and one of the authors of the study published in the latest edition of the journal Genome Biology.
"Those are fascinating ecological, physiological features that have evolved in turtles ... so as a biologist those are fascinating things to learn more about, more about the genes that allow them to do that," Shaffer said.
Shaffer and his colleagues hope solving the DNA puzzle may one day lead to innovations in treating hypothermia, frostbite, heart attacks or strokes.
The DNA confirmed for scientists that the turtles have evolved at a ... turtle's pace, and have in fact changed little in design over the past 210 million years.
"Turtles are nothing short of an enigma," Richard K. Wilson, director of Washington University's Genome Institute and one of the authors, said in a statement. "We could learn a lot from them."
In addition to their ability to freeze and thaw without suffering organ or tissue damage, they have longevity and continue to reproduce at advanced ages, he said.
Western painted turtles can live for more than 40 years, while other species of turtle live well over a century. Females can grow up to 25 centimetres long, while males grow up to 17 centimetres.
The DNA information — funded by the National Human Genome Research Institute at the National Institutes of Health in the United States — is being shared with 59 scientists around the world, including three researchers at UBC, Carlton and the University of Toronto for further study.
While Western painted turtles have fared well east of the Rocky Mountains, they are listed on the federal Species At Risk registry as a species of special concern in the Rocky Mountain area and west to the B.C. Interior.
They are listed as endangered in the coastal area that includes Vancouver Island, the Sunshine Coast, Metro Vancouver and the Fraser Valley because of the loss of wetlands and pace of urban development.
"Roads are a big threat. The female leaves the pond and tries to find a very open, sunny area to lay her eggs and often that means crossing a road," said Purnima Govindarajulu, a provincial government biologist and spokeswoman for its B.C. Frogwatch program.
"A turtle being a turtle, they're not moving very quickly so they're very susceptible to being killed on the road."
The provincial government has several programs aimed at saving the turtles, including creating nesting beaches so they don't have to cross roads.
There is also a genetic study being conducted at UBC Okanagan, and students from Thompson Rivers University are studying the effects of hydro dams on the reptiles.
There are 330 turtle species, and about half are considered threatened due largely to their popularity as a food dish in Asia, where lore says eating turtles promotes good health and long life.
Schaffer said he hopes the potential for medical advances might help save turtles.
"They're fascinating in their own right just as examples of unique biodiversity. They're important in terms of what they might say in terms of human health and welfare, and over half of them are threatened with extinction right now," he said.
"One of the messages of all this fascinating biology we're learning about is how important it is to preserve the little bit of turtle biodiversity that we have."