January 12, 2009, 5:14 pm
RNA replicates... alone!
One of the most puzzling questions of how molecular life could begin is how can RNA, the first type of nucleic acid to carry hereditary information even before DNA, copy itself without the help of proteins? Scientists have made the first artificial RNA molecule that can copy itself over and over again, without help from proteins.
So what, you ask? What is the big deal about a small molecule, RNA, that copies itself all by itself?
Well, the deal goes back to our early understanding of how heredity works. The central dogma of molecular biology has DNA as the main player in the role of heredity - DNA can copy itself (DNA replication) and can also be copied into RNA molecules (transcribed) which are used to make proteins.
That all sounds fine until you start to ask, where did the first genetic material come from?
In order to copy itself, DNA needs proteins, and to make proteins, RNA molecules copied from DNA are needed. Hmmm. Can't have one without the other!
RNA that can copy itself many times without needing proteins is a vital piece in the puzzle for understanding how the genetic material evolved to the 'DNA to RNA to protein' situation that we have in living organisms today.
Read the article in Greek