Question

Scientists originally thought RNA was simply a messenger that passes information between the DNA and the protein generating structures within a cell. Now, however, evidence is emerging that RNA plays a far more dynamic role in determining the phenotype of an organism. Provide evidence supporting this theory and explain how the original primitive RNA sequences could give rise to the diversity of life that inhabits Earth today.

This is a 5 point essay question, thanks!

Answer 1

Only since twenty years ago we have begun to understand the complex role that RNA plays in our genome. Not so long ago, we only knew about the RNAs that were included in the processes of the central dogma, the passing down of information from DNA to proteins, but nowadays we know about various types of non-coding RNA as well.

The non-coding RNAs play a key role in the regulation of gene expression.

Small nuclear RNAs have a role in cutting the introns in the primary mRNA
sequence, micro RNAs, and small interfering RNAs have roles in methylation and RNA interference. So, different RNA molecules can alter the phenotype on different levels of gene expression, editing the mRNA in different ways, blocking and degrading certain RNA molecules or methylating genes in order to decrease or increase their expression.

Recent studies have also debunked the misconception that the RNA molecule is too simple to may have been the initial bearer of genetic information. With the discovery of the ribozymes, RNA molecules that can both catalyze reactions(like enzymes do) and copy itself, it became clear that there could be a strong possibility of RNA being the primary carrier of genetic information in the pre-biotic era.