The origin of life remains one of man’s most basic and puzzling questions. One theory, the RNA World Hypothesis, developed in 1968 by Nobel Prize winner Walter Gilbert, posits that ribonucleic acid (RNA), a cousin of DNA, was the catalytic engine responsible for the initiation of life. Several Nobel prizes have been awarded to scientists for contributing to this theory.
Thomas Steitz’ research on the three-dimensional structure of the ribosome was a revolution of the RNA World Hypothesis, demonstrating that RNA was indeed responsible for assembling proteins.
“Francis Crick suggested in 1968, that maybe the ribosome should be all RNA. This was long before anybody knew much of anything about it,” Steitz explained. “The reason being, how could you have ‘a machine’ that makes proteins be made out of proteins if, as a cell, you haven’t learned how to make proteins yet? It is the chicken and the egg problem. How do you have proteins made by proteins? You can’t have that. If you have RNA make proteins, then that works.
“What we were able to see was that indeed, the essential components of what the ribosome has to achieve are facilitated by the RNA. That means the original ancestral ribosome was probably, almost certainly, all RNA. The ribosome has been a very good topic for understanding evolution because it goes way back to the beginning.”