Document Detail


The genomic complexity of micro B chromosomes of Brachycome dichromosomatica.
MedLine Citation:
PMID:  11862452     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A major sequence component of the micro B chromosome of Brachycome dichromosomatica (2 n=4) is the tandem repeat Bdm29, which was found by in situ hybridisation to be distributed along the entire length of the chromosome. A high copy number of this sequence does not occur as a regular feature of the A chromosomes in this species but it was found in infrequent individuals in two wild populations that were analysed. In these instances Bdm29 is localised within heterochromatic, polymorphic segments on the long arm of chromosome 1. The origin of the micro B chromosomes was investigated by determining whether they are related to this A chromosome polymorphism by simple excision and/or integration. Results obtained by using Bdm29, together with a newly isolated repeat sequence, Bdm54, and a number of other sequences known to occur on the micro B chromosome, as probes in in situ hybridisation and Southern analysis demonstrated that the formation of micro B chromosomes is a complex multistep process. The observation that the genomic organisation of the micro B chromosome is unlike anything found on the A chromosomes precludes their origin by simple excision and also indicates that micro Bs do not integrate directly into the A complement to form polymorphic heterochomatic segments.
Authors:
A Houben; D Verlin; C R Leach; J N Timmis
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2001-11-01
Journal Detail:
Title:  Chromosoma     Volume:  110     ISSN:  0009-5915     ISO Abbreviation:  Chromosoma     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2002-02-25     Completed Date:  2002-05-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985138R     Medline TA:  Chromosoma     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  451-9     Citation Subset:  IM    
Affiliation:
Molecular Biosciences (Genetics), Adelaide University, SA, Australia 5005. houben@ipk-gatersleben.de
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MeSH Terms
Descriptor/Qualifier:
Asteraceae / genetics*
Base Sequence
Cell Nucleus / chemistry,  genetics
Chromosomes*
DNA, Plant / analysis
Diploidy
Genome, Plant
Genotype
Heterochromatin
In Situ Hybridization, Fluorescence
Karyotyping
Metaphase
Molecular Sequence Data
Plant Leaves / genetics
Polymorphism, Genetic
Repetitive Sequences, Nucleic Acid
Sequence Analysis, DNA
Telomere / genetics
Chemical
Reg. No./Substance:
0/DNA, Plant; 0/Heterochromatin

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