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

Posted: January 8, 2015 at 7:49 am

Since the discovery of how DNA encodes genetic information, most research on the evolution of life has focused on genes. According to the "selfish gene" theory, cells and organisms exist simply as packages to protect and transmit genes. New research challenges this idea, proposing instead that if anything is "selfish" it must be the ribosome. That up-ends everything we think we know about the evolution of life and, in fact, the function of ribosomes themselves.

What came first in the evolution of life? Until now, scientists have answered the question with three letters: DNA. But In a father-daughter collaboration published in Journal of Theoretical Biology, Dr. Meredith Root-Bernstein, Aarhus University, Denmark, and Dr. Robert Root-Bernstein, Michigan State University, USA, provide evidence that the question should rather be answered with the word: Ribosomes.

The ribosome is a large and complex molecule found in all living cells. It contains the machinery for translating the genetic information from DNA into the proteins that perform all the work of the cell and make up most of its structure.

"Ribosomes are made of three protein-encrusted RNA strands that textbooks tell us are purely structural, but we show that ribosomal RNA once acted as the genes, mRNAs and tRNAs required to make its own components -- and gave rise to these structures in modern cells," says Dr. Meredith Root-Bernstein.

What does DNA want?

The father-daughter research collaboration started when Meredith was re-reading her father Robert Root-Bernstein's 1989 book Discovering.

"Halfway through the book, inspired by the discovery strategies my father discusses there, I looked up and asked "what does DNA want?" It may sound strange to anthropomorphize a large molecule. However, the selfish gene theory is commonly expressed in a scientific short-hand as "DNA wants to replicate itself." But I wondered if this is really what DNA wants," Dr. Meredith explains.

When organic chemists anthropomorphize molecules, they say that molecules "want to be in their lowest energy conformation." This means that when they have energy molecules can move into different conformations, but they have a resting position that they come back to.

The resting position of DNA is very tightly curled up. It is so hard to unravel that researchers do not fully understand how the various helper molecules uncurl and unzip it for replication and translation.

Thus, as Meredith realized, from the organic chemistry point of view, the answer to "what does DNA want" is: It wants to sit curled up in a knot. DNA does not want to replicate or translate.

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

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