Life on Earth today is based on two fundamental classes of molecules, the molecules of the genetic
material, RNA and DNA, and the molecules of life's machines, proteins. At the dawn of life billions
of years ago, RNA apparently reigned pretty much by itself, DNA and proteins coming on board later. Eventually,
early living organisms began to specialize and then split into the three domains, Bacteria, Archaea, and Eucarya.
From there, life continued to evolve, branching out into the
many and diverse forms that surround us today. Life itself gave scientists the clock to study
this process of evolution. The clock is nothing less but the central machine of all living cells, the ribosome,
that reads genetic information and translates it into proteins. The first to read this clock and
establish the modern science of evolution was Carl Woese. The ribosome differs greatly from other
cellular machines in that it is made mainly of RNA, only to a smaller part of proteins, the latter
being added in the course of evolution. A recent report
investigated the interaction between RNA and proteins in the ribosome. The researchers examined the
details of how RNA and proteins evolved together and showed how such details
can lead to better understanding of the ribosome as a machine. More details are available at the researchers'