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Influences of array size and homogeneity on minisatellite mutation
Author(s) -
Buard Jérôme,
Bourdet Agnès,
Yardley Jane,
Dubrova Yuri,
Jeffreys Alec J.
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.12.3495
Subject(s) - minisatellite , library science , genetics , biology , microsatellite , computer science , gene , allele
Unstable minisatellites display high frequencies of spontaneous gain and loss of repeats in the human germline. Most length changes arise through complex recombination events including intra‐allelic duplications/deletions and inter‐allelic transfers of repeats. Definition of the factors modulating instability requires both measurement of mutation rate and detailed analysis of mutant structures at the level of individual alleles. We have measured mutation rates in sperm for a wide range of alleles of the highly unstable human minisatellite CEB1. Instability varies by three orders of magnitude between alleles and increases steadily with the size of the tandem array. Structural analysis of mutant molecules derived from six alleles revealed that it is the rate of intra‐allelic rearrangements which increases with array size and that intra‐allelic duplication events tend to cluster within homogeneous segments of alleles; both phenomena resemble features of trinucleotide repeat instability. In contrast, inter‐allelic transfers occur at a fairly constant rate, irrespective of array length, and show a mild polarity towards one end of the minisatellite, suggesting the possible influence of flanking DNA on these conversion‐like events.