Scientists rebuild ancient proteins to reveal primordial Earth's t...(s. Each bacterial species has a slightly...)

Armed with information about when bacterial species evolved, the scientists rebuilt 31 elongation factors from 16 ancient species. By comparing the heat sensitivity of the reconstructed proteins, they were able to discern how Earths temperature changed over the ages.

Although the concept of ancestral gene resurrection was proposed more than 40 years ago, the development of efficient gene synthesis has only recently enabled the synthesis of ancestral genes, said Sridhar Govindarajan, Ph.D., co-author of the paper and vice president of informatics at DNA2.0, a California-based company that constructed the genes. Gene synthesis allows for a direct route from a calculated gene sequence to a protein that can be tested for function in the laboratory.

Almost all bacteria are related if you go back far enough, the scientists said. Even organisms that like extreme heat are related to organisms that are very sensitive to temperature change. The key is determining when, during Earths history, each type of bacteria came into existence.

Remarkably, our results are nearly identical to geologic studies that estimate the temperature trend for the ancient ocean over the same time period. The convergence of results from biology and geology show that Earths environment has continuously been changing since life began, and life has adapted appropriately to survive, Gaucher said.

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