Dec 17, 2010 14:22 GMT  ·  By
The seasonal loss of the Arctic ice sheet could lead to the extinction of some rare marine animals and the loss of many adaptive genes, through interbreeding.
   The seasonal loss of the Arctic ice sheet could lead to the extinction of some rare marine animals and the loss of many adaptive genes, through interbreeding.

Three researchers from the NOAA, University of Massachusetts Amherst and University of Alaska, say that the seasonal loss of the Arctic ice sheet could lead to the extinction of some rare marine animals and the loss of many adaptive genes, through interbreeding.

For some time now, scientists say that the Arctic Ocean will be ice-free in summer by the end of this century.

Marine mammalogist and first author Brendan Kelly of the National Oceanic and Atmospheric Administration’s marine mammal lab in Juneau, with conservation geneticist Andrew Whiteley of the University of Massachusetts Amherst and evolutionary biologist David Tallmon of the University of Alaska, pull the alarm signal in the latest issue of the journal Nature.

They warn that immediate monitoring and serious studies of the rare, threatened or endangered species in the Arctic (polar bears, whales and seals) in the coming decades is absolutely necessary, if we want to do something before it's too late, and populations disappear because of interbreeding.

The scientists say that these animals have developed, over thousands of years, genes that have provided very precise adaptations, so that they could thrive in this very hostile environment.

As the natural iced barrier will disappear, the animals will interbreed and mix their gene pools, and even though in the first generation this could be beneficial for them, the situation is much more complex than that and biologists don't really know what to expect.

There is a big risk that in later generations, as the genomes mix and the environment-adapted traits are recombined, the hybridization process will have more negative effects.

Normally, hybridization is nature's way of creating novelty but the researchers think that the genes that once allowed the animal to thrive in its specific environment could be diluted and the animals could lose their ability to survive and reproduce in that same environment.

Or, in the case of interbreeding between the rare North Pacific right whale – with under 200 individuals believed to be left, and the much more frequent bowhead whales, this could mean extinction of the smaller population.

Along with their Nature article, the three researchers made a chart containing 22 marine mammal species that could be at risk of hybridization.

This phenomenon has, apparently, already started, and some individuals have already been documented by DNA testing.