Document Detail


Two modes of germline instability at human minisatellite MS1 (locus D1S7): complex rearrangements and paradoxical hyperdeletion.
MedLine Citation:
PMID:  12748906     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Minisatellite MS1 (locus D1S7) is one of the most unstable minisatellites identified in humans. It is unusual in having a short repeat unit of 9 bp and in showing somatic instability in colorectal carcinomas, suggesting that mitotic replication or repair errors may contribute to repeat-DNA mutation. We have therefore used single-molecule polymerase chain reaction to characterize mutation events in sperm and somatic DNA. As with other minisatellites, high levels of instability are seen only in the germline and generate two distinct classes of structural change. The first involves large and frequently complex rearrangements that most likely arise by recombinational processes, as is seen at other minisatellites. The second pathway generates primarily, if not exclusively, single-repeat changes restricted to sequence-homogeneous regions of alleles. Their frequency is dependent on the length of uninterrupted repeats, with evidence of a hyperinstability threshold similar in length to that observed at triplet-repeat loci showing expansions driven by dynamic mutation. In contrast to triplet loci, however, the single-repeat changes at MS1 exclusively involve repeat deletion, and can be so frequent--as many as 0.7-1.3 mutation events per sperm cell for the longest homogeneous arrays--that alleles harboring these long arrays must be extremely ephemeral in human populations. The apparently impossible existence of alleles with deletion-prone uninterrupted repeats therefore presents a paradox with no obvious explanation.
Authors:
Ingrid Berg; Rita Neumann; Håkan Cederberg; Ulf Rannug; Alec J Jeffreys
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2003-05-12
Journal Detail:
Title:  American journal of human genetics     Volume:  72     ISSN:  0002-9297     ISO Abbreviation:  Am. J. Hum. Genet.     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-05-15     Completed Date:  2003-07-22     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0370475     Medline TA:  Am J Hum Genet     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1436-47     Citation Subset:  IM    
Affiliation:
Department of Genetic and Cellular Toxicology, Stockholm University, Stockholm, Sweden. Ingrid.Berg@genetics.su.se
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MeSH Terms
Descriptor/Qualifier:
Alleles
Carcinoma / genetics
Colorectal Neoplasms / genetics
DNA, Satellite / analysis
Gene Deletion*
Gene Frequency
Genome, Human
Germ Cells
Germ-Line Mutation / genetics*
Heterozygote
Homozygote
Humans
Male
Minisatellite Repeats / genetics*
Sequence Deletion
Spermatozoa / physiology
Chemical
Reg. No./Substance:
0/DNA, Satellite
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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