Equilibrium distributions of microsatellite repeat length resulting from a balance between slippage events and point mutations.


Journal Article

We describe and test a Markov chain model of microsatellite evolution that can explain the different distributions of microsatellite lengths across different organisms and repeat motifs. Two key features of this model are the dependence of mutation rates on microsatellite length and a mutation process that includes both strand slippage and point mutation events. We compute the stationary distribution of allele lengths under this model and use it to fit DNA data for di-, tri-, and tetranucleotide repeats in humans, mice, fruit flies, and yeast. The best fit results lead to slippage rate estimates that are highest in mice, followed by humans, then yeast, and then fruit flies. Within each organism, the estimates are highest in di-, then tri-, and then tetranucleotide repeats. Our estimates are consistent with experimentally determined mutation rates from other studies. The results suggest that the different length distributions among organisms and repeat motifs can be explained by a simple difference in slippage rates and that selective constraints on length need not be imposed.

Full Text

Duke Authors

Cited Authors

  • Kruglyak, S; Durrett, RT; Schug, MD; Aquadro, CF

Published Date

  • September 1998

Published In

Volume / Issue

  • 95 / 18

Start / End Page

  • 10774 - 10778

PubMed ID

  • 9724780

Pubmed Central ID

  • 9724780

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.95.18.10774


  • eng