A new class of molecules that contain genetic information has been discovered by molecular biologist Larry Simpson of the University of California at Los Angeles. Simpson reported in January that the new molecules were isolated from a family of parasites, called kinetoplastids, that cause widespread tropical diseases, such as Chagas' disease and sleeping sickness. The discovery provides fundamental new information on the process by which genetic information is converted into living organisms.The new discovery solves a riddle presented 18 months earlier when Simpson and geneticist Kenneth Stuart of the University of Washington reported observations that contradict one of the prime tenets of biology—that all genetic information is contained in DNA and that this information is faithfully copied in the production of proteins and other cellular components. Simpson and Stuart found that at least five genes in kinetoplastid DNA are so garbled that they cannot be used to produce functional proteins. But somehow, the messenger ribonucleic acid (mRNA) that is normally copied from DNA and serves as a 'working blueprint' was cleaned up and given the correct genetic information. The mystery was where the correct information came from.Simpson found that the correct genetic information comes from pieces of RNA that he named guide RNA (gRNA). The gRNA was found in mitochondria, energy-producing bodies, within kinetoplastid cells. The presence of the gRNA had been known before, but not its function. Simpson thus solved two mysteries at once. He has not yet proved that such RNA editing occurs in other species, but he noted that human DNA contains long sequences of nucleic acid that look superficially like genes but that are missing certain key elements. These pseudogenes are similar to the garbled genes in kinetoplastids, he said, and the information they contain may be processed in the same manner.
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