| 'Climate' genes leave species vulnerable|
|A new study has found that the genes of many species won't allow them to adapt to a warming climate.|
The research, published in today's edition of Science, suggests biodiversity will be harder to maintain than previously thought.
Biologist and author Professor Ary Hoffmann, of the University of Melbourne, says the study looked at the evolutionary potential of different species of vinegar fly, which live in both tropical and temperate regions of Australia.
Hoffmann says he and his team wanted to know whether all the fly species could adapt to climate changes, or if adaptibility depends on where the species lives.
They looked at the flies ability to adapt to cold and dry environments to assess their evolutionary potential.
Hoffmann says compared to the other species of flies, those from tropical regions had limited ability to adapt.
Lack of diversity
He says this is because tropical flies have low genetic diversity in the traits that matter.
"In the genes that allow them to adapt to cold temperature and aridity they are lacking diversity."
Hoffmann says this finding was quite a surprise.
"Generally the assumption is that a large population can adapt to almost anything."
He says he's not sure why evolution would promote such limited genetic diversity in important adaptive traits, but he has some theories.
A tropical species of fly would find all its resources in a tropical habitat, says Hoffman
"If that happens for a few hundred years then the genes that allow them to go outside that environment may simply start decaying."
He says over time genes acquire mutations, and "if you accumulate enough you lose the function of those genes."
Hoffmann says a genetic "trade-off" could be the other reason some species may have limited genetic ability to adapt.
A gene could be well suited for one environment and not for another, he says.
Hoffmann says the part of the gene that's not well suited will be lost, which means there is little room for the species to adapt if the climate shifts.
The consequence of animals having little genetic ability to adapt could mean animals get "stuck" in a specific ecosystem, Hoffman says.
"Once you've become a specialist in a particular type of environment it can be very hard to break out of it."
He says the unfortunate reality is that there are far more animals who are specialists in their environment than generalists.
"There are many more species of tropical animals that have very narrow climate distributions than not."
Hoffman says his team are now trying to locate the specific genes associated with these adaptive traits.
They also plan to conduct similar studies on the adaptive ability of other species.
"We're looking at alpine plants to see whether the same phenomenon is happening here," says Hoffman.