Document Detail

Extensive direct-tandem organization of a long repeat DNA sequence on the Y chromosome of chinook salmon (Oncorhynchus tshawytscha).
MedLine Citation:
PMID:  9493353     Owner:  NLM     Status:  MEDLINE    
A long repetitive DNA sequence (OtY8) has been cloned from male chinook salmon and its genomic organization has been characterized. The repeat has a unit length of 8 kb and is present approximately 300 times per diploid male nucleus. All internal fragments within the 8-kb repeat segregate from father to son, suggesting that the entire repeat unit is located on the Y chromosome. The organization of this sequence into an 8-kb repeat unit is restricted to the Y chromosome, as are several male-specific repeat subtypes identified on the basis of restriction-site variation. The repeat possesses only weak internal sequence similarities, suggesting that OtY8 has not arisen by duplication of a smaller repeat unit, as is the case for other long tandem arrays found in eukaryotes. Based on a laddered pattern arising from partial digestion of genomic DNA with a restriction enzyme which cuts only once per repeat unit, this sequence is not dispersed on the Y chromosome but is organized as a head-to-tail tandem array. Pulse-gel electrophoresis reveals that the direct-tandem repeats are organized into at least six separate clusters containing approximately 12 to 250 copies, comprising some 2.4 Mb of Y-chromosomal DNA in total. Related sequences with nucleotide substitutions and DNA insertions relative to the Y-chromosomal fragment are found elsewhere in the genome but at much lower copy number and, although similar sequences are also found in other salmonid species, the amplification of the repeat into a Y-chromosome-linked tandem array is only observed in chinook salmon. The OtY8 repetitive sequence is genetically tightly associated with the sex-determination locus and provides an opportunity to examine the evolution of the Y chromosome and sex determination process in a lower vertebrate.
R H Devlin; G W Stone; D E Smailus
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of molecular evolution     Volume:  46     ISSN:  0022-2844     ISO Abbreviation:  J. Mol. Evol.     Publication Date:  1998 Mar 
Date Detail:
Created Date:  1998-03-26     Completed Date:  1998-03-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0360051     Medline TA:  J Mol Evol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  277-87     Citation Subset:  IM    
Fisheries and Oceans Canada, Vancouver, B.C., Canada.
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MeSH Terms
Base Sequence
Chromosome Mapping
DNA / genetics*
DNA Transposable Elements
Linkage (Genetics)
Molecular Sequence Data
Repetitive Sequences, Nucleic Acid*
Salmon / genetics*
Sequence Homology, Nucleic Acid
Sex Determination (Genetics)
Species Specificity
Y Chromosome*
Reg. No./Substance:
0/DNA Transposable Elements; 9007-49-2/DNA

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

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