[excerpt] A billion years ago, the ancestors of today's bacteria thrived in an environment similar to a Yellowstone hot spring, suggesting Earth may have been a much warmer place closer to the time when life originated.
So say two University of Florida scientists who have used the newly developed techniques of 'paleobiochemistry' to reconstruct ancient bacterial proteins based on similarities in the genetic sequences of modern proteins. The resurrected proteins proved most stable and functional at temperatures between 130 and 150 degrees Fahrenheit, implying that ancient bacteria lived in a hot springs-like soup warmer than most life can tolerate today.
The research, which appeared Sept. 18 in the journal Nature, is expected to enliven a longstanding debate about the temperatures of Earth when life consisted only of microbes, long before the appearance of animals about a half billion years ago. The findings also may help narrow the search for life on other planets, said Eric Gaucher, a National Research Council fellow and post-doctoral associate at the University of Florida, who is the lead author of the paper.
"If you're going to search for life on other planets, you can't just randomly put a probe down and look for life," Gaucher said. "You want to land in a spot that you think is the most probable for hosting life. So having some idea of the temperature zone where you should put the probe will be helpful."
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