Nobody knows quite how life originated on Earth, but most scientists agree that living cells did not abruptly appear from nonliving cells in a single step. Instead, there were probably a series of pre-cellular life forms that arose from nonliving chemicals and eventually led to a living cell, one that could undergo metabolism and reproduce. One of the most well-known theories of pre-cellular life is the RNA world theory, which proposes that life based on RNA predates current life, which is based on DNA, RNA, and proteins. But recently, scientists have been wondering what may have preceded RNA. In a new study, a team of scientists from Germany has suggested that the ability to self-replicate may have first emerged in the form of an RNA reactor, which they show can transmit information.
The scientists, Benedikt Obermayer, Hubert Krammer, Dieter Braun, and Ulrich Gerland of the Ludwig Maximilians University of Munich, have published their study on the prebiotic RNA reactor in a recent issue of Physical Review Letters. The biggest piece of support for RNA molecules as pre-life forms is that RNA can act as both genes (to store information) and enzymes (to catalyze chemical reactions). Like DNA, RNA is made up of a long chain of nucleotides. However, scientists do not know how a self-replicating RNA system could have arisen from a pool of random polynucleotides.
To address this question, Obermayer, et al., have turned to RNA replicators. As described in previous research, RNA replicators can transmit information from one molecule to another so that the information survives even when the original carrier molecules have become degraded. Here, the researchers have investigated how RNA replicators may have arisen from simpler RNA reactors billions of years ago.
“We show that a combination of simple physico-chemical mechanisms can greatly facilitate the spontaneous emergence of a prebiotic evolutionary system, such as envisaged by the RNA world,” Gerland told PhysOrg.com.