You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Molecular Evolution Over the Mutational Landscape
John H. Gillespie
Vol. 38, No. 5 (Sep., 1984), pp. 1116-1129
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2408444
Page Count: 14
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
A model of molecular evolution by natural selection is described. The dynamics of the model are determined to a great extent by the nature of the mutational process of DNA. This is due to the very low nucleotide mutation rate that effectively limits natural selection to those alleles that differ from the currently fixed allele by a single nucleotide. As a consequence, it is shown that evolution should proceed in a series of bursts if natural selection is the main mechanism for the change. A typical burst of evolution is shown to involve about 1.5 to 2.5 allelic substitutions on average. One consequence of these bursts is to elevate the variance to mean ratio in the number of substitutions per unit time to a level as is commonly observed in the protein evolution data. These results appears to be very robust to many of the particulars of the model because of the role played by extreme value theory in determining the fitnesses of the alleles.
Evolution © 1984 Society for the Study of Evolution