Mutational dynamics of short tandem repeats in human genome

National Institute of Chemistry - P.O. Box 660, 1001 Ljubljana, Slovenia

Received: 28 April 2003
Accepted: 5 November 2003

Abstract

The evolutionary dynamics of short tandem repeats of nucleotide sequences of the human genome is studied. It is shown that a model due to which the evolutionary repeat dynamics consists of elongations and shortenings of the repeats, combined with point mutations, is degenerate in the sense that an ambiguity exists regarding the role of point mutations and slippage asymmetry. By introducing a measure of the correlations between the positions of the repeats along the DNA sequences we were able to remove the degeneracy and to show that the slippage events which are the main factor in repeat evolution exhibit more frequent shortenings than elongations.