The first set of genes triggers the formation of chaperones that prevent proteins from unraveling, while the second set creates proteins that shepherd damaged material away.
This could have implications for climate change and how a key species like musselsfundamental to the ecology of inter-tidal rocky zoneswould adapt to a hotter world.
In addition, there are implications for understanding sudden summer mortality syndrome, a mysterious die-off that can devastate oyster farms, and which is believed to be linked to a stress event like heat.
Gene oscillation as survival strategy
Expressing genes in waves appears to be a survival strategy, one that has been seen in lab experiments involving yeast.
"There are certain physiological processes that are fairly incompatible, like respiration and cell division," Gracey explained.
Respiration creates free radicals, and if an organism undergoes cell division at the same time, those free radicals could damage DNA. (This is partly why antioxidants in green tea and pomegranates are popular these days, since they remove free radicals.)
By keeping respiration and cell division separate, mussels can decrease the chances of such cell damagean advantage in such extreme conditions.
What controls the cycles?
In humans, the circadian rhythm is also a cycle that involves waves of gene expression, but unlike the mussel cycles, it has consistent intervals regulated by light.
"Periods are typically constant, and typically they're following something related to a 24-hour cycle," Gracey noted. "Our data doesn't conform to that."
It's not yet clear what is driving the cycles in mussels. It could be temperature, how much time is spent out of the water, or the opportunity to feedbut it's hard to pin down a single variable.
(A new grant from the National Science Foundation will help Gracey and colleagues tackle t
|Contact: Terah DeJong|
University of Southern California