Over The Horizon

From Sheep to Whales

Taking DNA samples from six-metre Beluga whales is a little different from sampling sheep, but Fiona Buchanan will soon be using her sheep genetic profiling skills on the whales of the Arctic region for the Canadian Department of Fisheries and Oceans.

Buchanan's recent PhD studies at Otago University concentrated on using microsatellites -- small repetitive groups of DNA found on the chromosomes -- to look at variation in the genetic make-up of an animal. The technique aids in characterising genes, establishing breeds and pedigrees, and tracing the evolutionary relationship between breeds.

It was known that microsatellites are important for genetic linking within species, but relatively little else is understood about them. Buchanan's studies proved for the first time that they could also be used to identify different breeds.

While Buchanan has been using her skills to genetically profile sheep, she is shortly to apply the technique to genetic identification of the Beluga whale populations around Hudson Bay. Buchanan says that aerial photographs have been used to provide a rough indication of numbers, but that Canadian authorities do not have any accurate figures on the whale population and whether it is growing or not. The whales are a traditional prey of local Inuit.

More importantly, little is known about the age structure and reproductive capabilities of the various whale populations, and the Canadians hope that their new New Zealand expert will be able to provide this information. If it's found, for example, that young or breeding animals are low in number, then obviously management strategies will need to be revised.

Buchanan will be taking DNA samples from the whales, using microsatellite techniques to determine the family structures. While that sounds relatively straightforward, getting a tissue sample from a whale -- even a small whale -- will not be easy, compared to taking blood from a sheep.

The easiest way to extract a whale DNA sample has been to take it from the liver of whales which have already died. Harpoons have been used to draw plugs of skin from whales without killing them, but this is not an ideal approach. In New Zealand, skin tissue samples from whales off Kaikoura are simple to get -- these whales have a "dandruff" problem and suitable patches of skin slough off regularly.

So one of Buchanan's first jobs will be to design a suitable sampling strategy. Buchanan will be based at the Marine Mammal Laboratory at the Fresh Water Institute in Winnepeg, Canada.