Document Detail


Independent fusions and recent origins of sex chromosomes in the evolution and diversification of glass knife fishes (Eigenmannia).
MedLine Citation:
PMID:  20571513     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The genus Eigenmannia comprises several species groups that display a surprising variety of diploid chromosome numbers and sex-determining systems. In this study, hypotheses regarding phylogenetic relationships and karyotype evolution were investigated using a combination of molecular and cytogenetic methods. Phylogenetic relationships were analyzed for 11 cytotypes based on sequences from five mitochondrial DNA regions. Parsimony-based character mapping of sex chromosomes confirms previous suggestions of multiple origins of sex chromosomes. Molecular cytogenetic analyses involved chromosome painting using probes derived from whole sex chromosomes from two taxa that were hybridized to metaphases of their respective sister cytotypes. These analyses showed that a multiple XY system evolved recently (<7 mya) by fusion. Furthermore, one of the chromosomes that fused to form the neo-Y chromosome is fused independently to another chromosome in the sister cytotype. This may constitute an efficient post-mating barrier and might imply a direct function of sex chromosomes in the speciation processes in Eigenmannia. The other chromosomal sex-determination system investigated is shown to have differentiated by an accumulation of heterochromatin on the X chromosome. This has occurred in the past 0.6 my, and is the most recent chromosomal sex-determining system described to date. These results show that the evolution of sex-determining systems can proceed very rapidly.
Authors:
F Henning; C B Moysés; D Calcagnotto; A Meyer; L F de Almeida-Toledo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-06-23
Journal Detail:
Title:  Heredity     Volume:  106     ISSN:  1365-2540     ISO Abbreviation:  Heredity (Edinb)     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-19     Completed Date:  2011-05-04     Revised Date:  2012-02-01    
Medline Journal Info:
Nlm Unique ID:  0373007     Medline TA:  Heredity (Edinb)     Country:  England    
Other Details:
Languages:  eng     Pagination:  391-400     Citation Subset:  IM    
Affiliation:
Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Animals
Bayes Theorem
Cytogenetic Analysis
DNA, Mitochondrial / genetics
Evolution, Molecular*
Gene Fusion
Genetic Speciation
Genetic Variation*
Gymnotiformes / genetics*
Heterochromatin / metabolism
Karyotyping
Phylogeny
X Chromosome*
Y Chromosome*
Chemical
Reg. No./Substance:
0/DNA, Mitochondrial; 0/Heterochromatin

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


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