Novel mutation processes in the evolution of a haploid minisatellite, MSY1: array homogenization without homogenization.
The Y-specific locus MSY1 is the only known haploid minisatellite, and displays an extremely high degree of structural diversity which can be assayed by minisatellite variant repeat PCR (MVR-PCR). One group of alleles, in an African-specific class of Y chromosomes (haplogroup 8), behaves unusually in the conventional MVR-PCR assay, and sequencing demonstrates that this is because repeat units in these alleles contain an additional base substitution. We have designed a new MVR-PCR system to detect these novel variants, and show firstly that they are confined to the haplogroup 8 chromosomes, and secondly that the base substitution has spread through these arrays without the elimination of existing repeat variants. The sharing of a particular base substitution between otherwise distinct repeat types in these alleles represents evidence of a remarkable mutation process in their evolutionary history, in which the variant base must have been spread by a biased repair mechanism operating in very small patches within heteroduplexes.
Bouzekri
N
N
CNRS, UPR 8291, Centre d'Immunopathologie et de Genetique Humaine (CIGH), CHU Purpan, 31300 Toulouse, France.
Taylor
P G
PG
Hammer
M F
MF
Jobling
M A
MA
D014644:Genetic Variation; D006238:Haploidy; D006239:Haplotypes; D006801:Humans; D018598:Minisatellite Repeats / Q000235:genetics; D009549:Nigeria; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014998:Y Chromosome / Q000235:genetics*