Conservation geneticists can be thought of as molecular detectives. They use tiny scraps of evidence to piece together events of the past. Recently, they employed their innovative techniques to solve the strange case of the missing tammar wallabies, which is reported on the Australian Academy of Science's Nova: Science in the news web site (www.science.org.au/nova).

When colonial administrator Sir George Grey released a handful of tammar wallabies onto New Zealand's Kawau Island in 1870, he may have inadvertently performed a great service for conservation. The species was once widespread in South Australia, but in the late 1800s the population on mainland Australia was in decline, a victim of habitat destruction, fox predation and shooting. By the early 1900s, it was extinct on the mainland.

Fortunately, the species itself wasn't extinct. It still persisted on some islands, including Kangaroo Island. But these populations had been separated from the mainland population for around 10,000 years and were therefore likely to be quite different genetically. When the mainland population became extinct, the species lost a significant part of its genetic diversity.

Sir George didn't record where he obtained his animals, but it was an important question. If they were from the Australian mainland, then their descen-dants were the last survivors of an otherwise extinct population, and were likely to be of considerable value for biodiversity conservation.

The only way to determine their origin was to compare their genetic make-up with that of the Kangaroo Island population, so this was what conservation biologists at the Cooperative Research Centre for Marsupial Conservation and Management did. The research was funded by the Australian Research Council, and the evidence they uncovered was quite conclusive and great news for conservation. It showed that the Kawau Island colony had been established with animals from the mainland popula-tion. Land managers in South Australia are now considering plans to reintroduce the animals to their original range.

For further information about Nova: Science in the News contact Nancy Lane, 02 6247 5777 or nancy.lane@science.org.au

Academy Web site:
http://www.science.org.au/

Nova–Science in the news:
http://www.science.org.au/nova/

Primary investigations:
http://www.science.org.au/pi/