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Bone DNA Useful

Bones preserved for thousands of years are proving useful sources of high-quality DNA, enabling scientists to learn more about the relationships between different species, population groups and individuals from plants and animals long dead.

"It came as quite a surprise when we found we could extract good DNA from old bones," remarks Victoria University researcher Alan Cooper. "In fact, when we worked on a mummified moa, we obtained better DNA from the bones that from the surrounding mummified tissue."

Bone DNA is apparently well preserved because of a micro-environment which is protected from decay by the bone barrier. Cooper sees huge potential for using the technique in areas as diverse as the study of extinct animals, human migration mapping and disease investigations.

"We will be able to do population studies of an extinct animal, perhaps finding out how it went extinct, on the basis of its bones alone," he says. Cooper is working on his PhD thesis dealing with the evolution of New Zealand birds, and has used DNA analysis to show that kiwis are not as closely related to moas as has been believed.

The oldest animal DNA recovered to date is about 15,000 years old, from an insect trapped in amber, and rocks in Idaho have preserved plant DNA which is 16 million years old.

"The bone work is a huge jump forward in ancient genetic studies," says Cooper. "The possibilities are very exciting.

Oyster Pickup Possible

New Zealand's dying oyster grounds may benefit from research by MAF Fisheries scientist Bob Hickman. For the last two years, Hickman has worked on developing a low-tech, low-cost, effective way to hatch and rear flat or dredge oysters.

"With the Bluff oyster fishery devastated by the parasite Bonamia, farming oysters may be the only way to restore supplies," Hickman says. Bonamia has been detected in Wellington Harbour and Tasman Bay, although it appears benign at this stage.

Some 50,000 oyster spat, or seed oysters, have settled and are being reared at the Mahanga Bay aquaculture research centre in Wellington.

"Present growth rates indicate that we could have commercial sized oysters in under three years -- half the time it takes wild oysters to reach that size," says Hickman.

The main problem is producing enough oyster spat for farming, as wild oysters have a naturally low 5% level of incubating females in the population. Hickman hopes to boost that rate by exposing the hatchery's adult oysters to an increased supply of sperm and food.

"Interim results are promising, with ten percent of the first batch incubating," he says, adding that another two years will be needed before the success of the research can be assessed.

Joan Begg, MAF Fisheries