University of Leicester
Balaresque_et_al-2014-Human_Mutation.pdf (1.13 MB)
Download file

Gene conversion violates the stepwise mutation model for microsatellites in y-chromosomal palindromic repeats.

Download (1.13 MB)
journal contribution
posted on 2015-05-28, 14:59 authored by Patricia Balaresque, Turi E. King, Emma J. Parkin, E. Heyer, D. Carvalho-Silva, T. Kraaijenbrink, P. de Knijff, C. Tyler-Smith, Mark A. Jobling
The male-specific region of the human Y chromosome (MSY) contains eight large inverted repeats (palindromes), in which high-sequence similarity between repeat arms is maintained by gene conversion. These palindromes also harbor microsatellites, considered to evolve via a stepwise mutation model (SMM). Here, we ask whether gene conversion between palindrome microsatellites contributes to their mutational dynamics. First, we study the duplicated tetranucleotide microsatellite DYS385a,b lying in palindrome P4. We show, by comparing observed data with simulated data under a SMM within haplogroups, that observed heteroallelic combinations in which the modal repeat number difference between copies was large, can give rise to homoallelic combinations with zero-repeats difference, equivalent to many single-step mutations. These are unlikely to be generated under a strict SMM, suggesting the action of gene conversion. Second, we show that the intercopy repeat number difference for a large set of duplicated microsatellites in all palindromes in the MSY reference sequence is significantly reduced compared with that for nonpalindrome-duplicated microsatellites, suggesting that the former are characterized by unusual evolutionary dynamics. These observations indicate that gene conversion violates the SMM for microsatellites in palindromes, homogenizing copies within individual Y chromosomes, but increasing overall haplotype diversity among chromosomes within related groups.


Funded by Wellcome Trust. Grant Number: 087576, 098051 AHRC EC Sixth Framework Programme. Grant Number: ERAS-CT-2003-980409 NWO (Netherlands Organisation for Scientific Research). Grant Number: 231-70-001



Human Mutation, 2014, 35 (5), pp. 609-617

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Biological Sciences/Department of Genetics


  • VoR (Version of Record)

Published in

Human Mutation


Wiley for Human Genome Variation Society, Wiley-Liss





Copyright date


Available date


Publisher version


PMCID: PMC4233959 Supplementary materials available via DOI: 10.1002/humu.22542