Document Detail


Complete meiotic pairing of crested newt chromosomes.
MedLine Citation:
PMID:  18470234     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
The longest chromosome (number 1) of Trituturus cristatus carries a heteromorphic segment, a heterozygosity perpetuated by a balanced lethal system. The heteromorphic segment is regarded as achiasmate and has been claimed to be asynaptic. Direct observations of chromosome pairing in spermatocytes and oocytes yield some cases where all homologous chromosomes appear to be completely paired, but the individual bivalents could not be identified as pachytene is not particularly clear in this species. The long arms of bivalent 1 usually remain attached by a terminal chiasma in spermatocytes of T. c. cristatus but the corresponding chiasma is only rarely present in T. c. carnifex spermatocytes. Synaptonemal complexes have been measured in both spermatocytes and oocytes of T. c. cristatus. A karyotype constructed from these measurements matches the main features of somatic and lampbrush chromosome karyotypes, indicating that all chromosomes must be completely paired and proportionately represented as synaptonemal complex. The total length of synaptonemal complex is much the same in spermatocytes and oocytes and is similar to the length in spermatocytes of Xenopus laevis. These two amphibian examples supplement a recent survey of other vertebrate classes to reinforce its conclusion that synaptonemal complex length is not related to genome size in vertebrates.
Authors:
H Wallace; B M Wallace
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Genome / National Research Council Canada = Génome / Conseil national de recherches Canada     Volume:  38     ISSN:  0831-2796     ISO Abbreviation:  Genome     Publication Date:  1995 Dec 
Date Detail:
Created Date:  2008-05-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8704544     Medline TA:  Genome     Country:  Canada    
Other Details:
Languages:  eng     Pagination:  1105-11     Citation Subset:  -    
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