Forget the selfish gene: Evolution of life is driven by the selfish ribosome, research suggests

Author: Aarhus University
Publication Date: January 7, 2015
URL: http://www.sciencedaily.com/releases/2015/01/150107101405.htm

Summary:
    Many scientists accept the "selfish gene" theory to explain the origins of life; it states that DNA came first in the evolution of life and coded for the synthesis of the proteins and nucleic acids found throughout the cell. However, Dr. Meredith Root-Bernstein and her father, Dr. Robert Root-Bernstein, have found evidence that suggests that the ribosome was the original structure that self-replicated and led to DNA. Molecules can change form when provided with energy, but they all have a natural resting position, the form that the molecule returns to. In this way, the resting position could be considered the molecule's "desired" form. While DNA rests in coils, "not wanting" to replicate or translate, ribosomes rest in a position than can readily translate DNA. This led the Root-Bernsteins to hypothesize that ribosomes were once capable of replication and protein synthesis. Upon close examination of the ribosomes of E Coli, they discovered that the ribosomal RNA contained structures that resembled ribosomal protein-encoding sequences, messenger RNA, and transfer RNA-encoding sequences. Thus, ribosomes may have originally been able to self-replicate, possibly before DNA could.

Relevance:
    This article relates directly to our unit on molecular genetics. The basis of the Root-Bernsteins' proposal is the structure of DNA and ribosomes. One of their pieces of evidence came from how DNA is found in coils for most of the cell's life. They also further explorer the structure of the ribosome. The ribosome had previously been thought to have a purely structural function; its two subunits are positioned well for tanslation, but the Root-Bernsteins examined the rRNA more closely. They were able to find indications about the existence of three types of RNA in the ribosome: the rRNA itself, mRNA sequences folded into the subunits, and coding regions for tRNA. In class, we learned about these types of RNA and their key roles in protein synthesis. Additionally, the article relates to evolution in the sense that the ribosome may have coded for the first forms of organisms. From the indication of the organelle's ability to self-replicate and code for the production of nucleic acids, the idea that organisms coded by ribosomes evolved into those coded by DNA is now a possibility.