|Volume 40 Number 12||Edmonton, Canada||February 21, 2003|
Researchers find genetic response to global warming
Changing climate prompts genetic change in squirrels
A University of Alberta biologist and his research team have discovered that North American red squirrels are changing their genetic make-up to cope with global warming. It is the first time scientists have been able to demonstrate a genetic response in an animal species to warmer conditions.
Until now, biologists have only been able to show some animals demonstrate flexibility, or plasticity, in adapting to changes in their surroundings from year to year. But Boutin's findings show the red squirrel evolving genetically, from generation to generation, to cope with environmental forces.
Dr. Stan Boutin of the U of A Department of Biological Sciences has been studying a population of the squirrels in the southwest Yukon for almost 15 years. The squirrels, faced with increasingly warm spring temperatures and a corresponding increase in the amount of food available, have advanced the timing of breeding by 18 days over the last 10 years.
Plasticity is measured by how an individual squirrel changes the timing of reproduction from one year to the next, compared to one generation to the next - which is the genetic response Boutin is studying.
To come up with their results, Boutin and his colleagues have closely monitored generations of squirrels in Kluane National Park, fitting the pups with ear tags and observing them from February until September. The researchers know each individual squirrel and who it is related to.
Using that information, the team employed an approach called quantitative genetics, long used in livestock breeding but rarely applied to a wild species. Through analytical modeling, the researchers were able to sort out how much of the squirrels' adaptation is due to genetics.
"This has never been done before. Other researchers have stopped at plasticity," said Boutin.
"Having those two pieces to the puzzle helps us solve whether it's a genetic difference or plasticity, and we found, yes, some of these changes are genetic," he added. "Only by having long-term lineages can we get at this research."
Although the discovery shows the red squirrel adapting well to its warmer environment, its future is still a concern to scientists, especially considering the rapid rate of climate change. Predicting the squirrel's threshold for change is also impossible, said Boutin, so it is difficult to know if the animal has reached its peak of "adaptation skills."
"These animals might be at the limit of their adaptability skills. If climate change continues at this very quick pace, there is a possibility the animal will become more and more precarious and unable to keep up with change," he said. "The worst-case scenario is the extinction of the species."
The next step is to look at different components of the genome to see if researchers can pinpoint more closely the set of genes responsible for these changes.
Other authors on the paper are Dr. Andrew McAdam from the University of Alberta, Dr. Denis Réale, from McGill University, and Dr. Dominique Berteaux from the Université du Québec. Research was supported by the Natural Sciences and Engineering Research Council of Canada.