Scientists Discover Possible Building Blocks of Ancient Genetic Systems in Earth's Most Primitive Organisms

ScienceDaily (Nov. 9, 2012) — Scientists believe that prior to the advent of DNA as Earth's primary genetic material, early forms of life used RNA to encode genetic instructions. What sort of genetic molecules did life rely on before RNA?

The answer may be AEG, a small molecule that when linked into chains forms a hypothetical backbone for peptide nucleic acids, which have been hypothesized as the first genetic molecules. Synthetic AEG has been studied by the pharmaceutical industry as a possible gene silencer to stop or slow certain genetic diseases. The only problem with the theory is that up to now, AEG has been unknown in nature.

A team of scientists from the United States and Sweden announced that they have discovered AEG within cyanobacteria which are believed to be some of the most primitive organisms on Earth. Cyanobacteria sometimes appear as mats or scums on the surface of reservoirs and lakes during hot summer months. Their tolerance for extreme habitats is remarkable, ranging from the hot springs of Yellowstone to the tundra of the Arctic.

"Our discovery of AEG in cyanobacteria was unexpected," explains Dr. Paul Alan Cox, co-author of the paper that appeared in the journal PLOS ONE. The American team members are based at the Institute for Ethnomedicine in Jackson Hole, and serve as adjunct faculty at Weber State University in Ogden, Utah.