RNA is able to store genetic information as DNA can, is able to catalyze biochemical reactions as protein enzymes can, and otherwise probably could have performed the basic biological tasks that would have been necessary in the first life forms.Īlthough origin-of-life researchers in recent decades have largely come to embrace the RNA World hypothesis, Sutherland, Krishnamurthy, Harvard's Jack Szostak and others have accumulated evidence that RNA and DNA may have arisen more or less all at once in the first life forms. Due in part to this lack of a demonstrated pre-life or "pre-biotic" chemical path connecting RNA to DNA, researchers in this field have been inclined to think that the simpler, more versatile one, RNA, was the basis for the first life forms-or at least for an early stage of life prior to the emergence of DNA. RNA ( ribonucleic acid) and DNA (deoxyribonucleic acid) are chemically very similar, but chemists have never been able to show how the one could have been converted to the other on the early Earth, except with the help of enzymes produced by early organisms. Krishnamurthy and his lab worked on the study with the lab of John Sutherland, DPhil, of the UK Medical Research Council's Laboratory of Molecular Biology at Cambridge, as part of the New York-based Simons Foundation's Collaboration on the Origins of Life. "These new findings suggest that it may not be reasonable for chemists to be so heavily guided by the RNA World hypothesis in investigating the origins of life on Earth," says co-principal investigator Ramanarayanan Krishnamurthy, Ph.D., associate professor of chemistry at Scripps Research. In contrast, the prevailing scientific view-the "RNA World" hypothesis-is that early life forms were based purely on RNA, and only later evolved to make and use DNA.
The discovery, published April 1 in Nature Chemistry, suggests that the first living things on Earth may have used both RNA and DNA, as all cell-based life forms do now.
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