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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Independent fusions and recent origins of sex chromosomes in the evolution and diversification of glass knife fishes (Eigenmannia)

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Author(s):
Henning, F. [1, 2] ; Moyses, C. B. [1] ; Calcagnotto, D. [1] ; Meyer, A. [2] ; de Almeida-Toledo, L. F. [1]
Total Authors: 5
Affiliation:
[1] Univ Sao Paulo, Dept Genet & Biol Evolut, Inst Biociencias, BR-05508090 Sao Paulo - Brazil
[2] Univ Konstanz, Lehrstuhl Zool & Evolut Biol, Fachbereich Biol, Constance - Germany
Total Affiliations: 2
Document type: Journal article
Source: HEREDITY; v. 106, n. 2, p. 391-400, FEB 2011.
Web of Science Citations: 22
Abstract

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. Heredity (2011) 106, 391-400; doi:10.1038/hdy.2010.82; published online 23 June 2010 (AU)