Document Detail


A comparison of the karyotype, constitutive heterochromatin, and nucleolar organizer regions of the new tetraploid species Xenopus epitropicalis Fischberg and Picard with those of Xenopus tropicalis Gray (Anura, Pipidae).
MedLine Citation:
PMID:  7151486     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A cytological analsis of the recently discovered tetraploid species Xenopus epitropicalis was carried out, using, in addition to the classical orcein method, silver staining and alkaline Giemsa banding techniques. The chromosome number of X. epitropicalis was found to be 40. The chromosomes can be grouped in to sets of four similar chromosomes (quartets), resembling the karyotype of X. tropicalis (2n = 20). However, C-band patterns revealed heterogeneity within the quartets, dividing each of them into two pairs of homologous chromosomes ("duets"). Moreover, there are differences in the position and distribution of constitutive heterochromatin between the karyotypes of X. epitropicalis and X. tropicalis. The secondary constrictions stained by silver and representing the nucleolar organizer regions (NOR's) appear in both species on chromosome pair 5. During meiosis, usually only bivalents appear in X. epitropicalis. The question of whether this species is of autopolyploid or allopolyploid origin cannot be answered with certainty; however, it seems to have a common ancestor with X. tropicalis.
Authors:
J Tymowska; M Fischberg
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cytogenetics and cell genetics     Volume:  34     ISSN:  0301-0171     ISO Abbreviation:  Cytogenet. Cell Genet.     Publication Date:  1982  
Date Detail:
Created Date:  1983-03-17     Completed Date:  1983-03-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0367735     Medline TA:  Cytogenet Cell Genet     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  149-57     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Chromosome Banding
Evolution
Female
Gene Amplification
Heterochromatin / ultrastructure*
Karyotyping
Male
Nucleolus Organizer Region / ultrastructure*
Polyploidy*
Species Specificity
Xenopus / genetics*
Chemical
Reg. No./Substance:
0/Heterochromatin

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


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