For decades, one foundational principle in the study of cellular biochemistry was that information flows in one direction. The information built into DNA’s double helixes is transferred to the RNA, and then the RNA serves as a messenger to the rest of the cell, in effect providing the same information to the mitochondria, telling them how to make the proteins that make up the cell’s cytoplasm. The information flow, on this conventional view, never goes backwards.
A scientist at Thomas Jefferson University, in Philadelphia, says he, and a large team of researchers he leads, have discovered exceptions to this rule. Specifically, human RNA can sometimes “write RNA messages into DNA,” says Dr. Richard Pomerantz, associate professor of biochemistry and molecular biology.
Pomerantz’ discovery was published in the June 11th issue of SCIENCE ADVANCES. He maintains that in a healthy cell, this reverse transcription may allow for RNA mediated repair of DNA. But it may also be a clue to the biochemistry of cancer. Perhaps the wrong information gets introduced into DNA, making a particular cell dysfunctional.
Strange New Worlds:
An implication that Pomerantz et al do not explicitly raise in this paper is that evolutionary theory may have to be re-worked. Ever since debates on the “continuity of the germ plasm” as the 20th century began, the neo-Darwinian synthesis has held that the flow of information in multicellular beings too is in only one direction, from the germ/gene to the organism, so that the only way organisms change over long periods of time is by random variation of the genes and the filtering process of survival. But if the flow of information can be reversed, even if only at the cellular level, then evolutionary mechanisms may be more complicated than has been thought.