The Genetic Equidistance Result of Molecular Evolution is Independent of Mutation Rates
The Burnham Institute for Medical Research, 10901 North Torrey Pines Roads, La Jolla, CA 92037.
- *Corresponding Author:
- Dr. Shi Huang
Email : [email protected]
Received Date: December 02, 2008; Accepted Date: December 22, 2008; Published Date: December 26, 2008
Citation: Shi H (2008) The Genetic Equidistance Result of Molecular Evolution is Independent of Mutation Rates. J Comput Sci Syst Biol 1: 092-102. doi: 10.4172/jcsb.1000009
Copyright: © 2008 Shi H. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The well-established genetic equidistance result shows that sister species are approximately equidistant to a simpler outgroup as measured by DNA or protein dissimilarity. The equidistance result is the most direct evidence, and remains the only evidence, for the constant mutation rate interpretation of this result, known as the molecular clock. However, data independent of the equidistance result have steadily accumulated in recent years that often violate a constant mutation rate. Many have automatically inferred non-equidistance whenever a non-constant mutation rate was observed, based on the unproven assumption that the equidistance result is an outcome of constant mutation rate. Here it is shown that the equidistance result remains valid even when different species can be independently shown to have different mutation rates. A random sampling of 50 proteins shows that nearly all proteins display the equidistance result despite the fact that many proteins have nonconstant mutation rates. Therefore, the genetic equidistance result does not necessarily mean a constant mutation rate. Observations of different mutation rates do not invalidate the genetic equidistance result. New ideas are needed to explain the genetic equidistance result that must grant different mutation rates to different species and must be independently testable.