The team then classified the deferentially expressed genes into functional groups and found that the genes most sensitive to temperature changes were primarily those involved in cell proliferation, growth, and development. The genes that varied according to location of origin were most often involved in cell adhesion, protein degradation, and protein biosynthesis.
"Our study shows that the response of larvae to changing conditions depends upon where the parent colonies lived," says Baums. "Clearly the coral larvae from Mexico and Florida respond differently to heat stress, even though they belong to the same species, showing adaptations to local conditions. The two populations have different adaptive potential."
Baums said she is excited by the clear evidence of local adaptations in populations that this study documented. Previous work by Baums and her colleagues has included experiments in restoring damaged coral reefs by creating larvae from controlled genetic crosses, growing them in captivity until they settle onto ceramic tiles, and then transplanting them into selected areas to replenish damaged reefs. Some crosses survive in higher-temperature water better than others, some survive in captivity better than others, and some settle more reliably onto the prepared tiles that are used to form or restore colonies. The new information from the current study will be invaluable in restoration work.
"Variation among populations in gene expression offers the species as a whole a better chance of survival under changing conditions," Baums said. "We might be able to screen adult populations for their ability to produce heat-resistant larvae and focus our conservation efforts on those reefs."
|Contact: Barbara K. Kennedy|