Mapping Antarctic Fish Chromosomes

December 4, 2005

Release from: ANSA.it

Genoa - Italy's base in Antarctica could play an important role in plans to map the chromosomes of fish in the region, an Italian researcher has revealed .

An idea that has been in the pipeline for some years is moving towards fruition, said Eva Pisano of Genoa University's Biology Department .

"Our main goal and the reason we come to Antarctica is to find different species of fish, in order to study the characteristics of their chromosomes," said Pisano, who is currently working on the Mario Zucchelli Station at the Italian base of Baia Terra Nova .

She is one of a team of Italian biologists trying to identify the number and form of the chromosomes of Antarctic fish .

"These fish are particularly fascinating as they all originated from a single progenitor," explained Pisano. "They have gradually diverged and there are now eight families of fish living in Antarctic waters." Over the millennia, these fish have undergone profound modifications to their structure and today, five out of the eight families produce an antifreeze protein .

This protein, which probably developed some 14 million years ago when water temperatures dropped, allows the fish to hide just under the Antarctic ice .

The group with this protein - known as the Antarctic Cod, even though it is not actually a cod - has a heartbeat of once every six seconds and is considered particularly important from a medical research point of view. It is hoped that studies could provide scientists with vital information on how to rectify situations in which the human heart beats too slowly .

Another unique group of Antarctic fish are the icefish, named for their pale, almost white colour. These are considered of inestimable scientific value as they are the only group of vertebrates that do not have red blood cells .

While other vertebrates use red blood cells to transport oxygen around the body, icefish transport oxygen through blood plasma instead .

So far, scientists have just completed the first detailed study of the chromosomes of one of these species, the Dissostichus Mawsoni, also known as the Mawson's Cod or the Antarctic Toothfish .

"This is an important step forward, although almost nothing has been done so far on the Antarctic fish chromosome project," said Pisano .

In fact, of the 130 species of Antarctic fish, scientists have only carried out substantial work on the chromosomes of 60 .

Pisano hopes that the growing support for the scheme, which will receive a further boost when the Mawson's Cod study is published, could eventually produce an international databank .

Pisano's remarks came at the start of the base's 21st summer expedition, financed by the Italian Education and Research Ministry in conjunction with the National Antarctic Research Program .

The Italian base is one of the largest stations in the Antarctic. Despite this, a recent survey by independent analysts concluded that the station was causing a minimal impact on its environment .