One of the most interesting thought is how life begun on world. Molecules that can make copies of themselves are thought to be crucial to understanding this process as they provide the basis for heritability, a critical characteristic of living systems. In my idea RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself.
In Vitro EvolutionThe replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other — what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits."This is the only case outside biology where molecular information has been immortalized,"Not content to stop there, the researchers generated a variety of enzyme pairs with similar capabilities. They mixed 12 different cross-replicating pairs, together with all of their constituent subunits, and allowed them to compete in a molecular test of survival of the fittest. Most of the time the replicating enzymes would breed true, but on occasion an enzyme would make a mistake by binding one of the subunits from one of the other replicating enzymes. When such "mutations" occurred, the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture. "To me that's actually the biggest result,".The research shows that the system can sustain molecular information, a form of heritability, and give rise to variations of itself in a way akin to Darwinian evolution. "Knocking on the Door of Life but the main value of the work, is at the basic research level. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts." , while the self-replicating RNA enzyme systems share certain characteristics of life, they are not themselves a form of life.