Genomic Studies: Sublethal Stress and Deficient Genetic "Tool Kits"
The comparative physiology approach extends to genomics. DNA microarrays, also known as "gene chips," enable researchers like Dr. Somero to compare thousands of DNA molecules from different species. This allows them to identify which genes are involved in the way a species reacts to the stress of climate change.
"When we look at what genes are turned on by sub-lethal temperature stressnot enough to kill the organism but enough to cause a problemwe can get a sense of the damage that is occurring in the cells," he said.
Such damage takes a heavy toll, he added. "It's a drain on the organism's energy supply. The organism has to channel energy into repairing the damage instead of into growth and reproduction."
Genomic studies are also revealing differences among species in the sets of "tools" found in their genomic "tool kits." The news for certain species may be grim: Comparing genomes has revealed that long-term evolution at stable temperatures may have stripped certain species of their ability to adapt to warming.
"This is particularly true in the Southern Ocean, where the consequences of evolving in an extremely cold and very stable thermal environment over a period of 10 to 15 million years are dramatic," said Dr. Somero. "The genes needed to allow these organisms to cope with rising temperatures may have been lost during evolution under stable cold conditions." Ectotherms of the Southern Ocean may be the most threatened of all marine species by rising temperatures.
Overall, the comparative approach gives researchers insights into the effects of global warming that they wouldn't other
|Contact: Donna Krupa|
American Physiological Society