Non-homologous sex chromosomes in two species of the genus Eigenmannia (Teleostei: Gymnotiformes)

Cytogenet Genome Res. 2008;121(1):55-8. doi: 10.1159/000124382. Epub 2008 May 7.


The Neotropical genus Eigenmannia is a fish group with unknown species diversity where representatives possess a broad range of chromosomal sex determining systems namely XY/XX, X(1)X(2)Y/X(1)X(1)X(2)X(2), ZZ/ZW as well as homomorphic sex chromosomes. To test the homology of two heteromorphic XY sex chromosome systems present in two sympatric populations, reciprocal cross-species FISH experiments were performed using probes derived by microdissection of X and Y chromosomes present in analyzed specimens of Eigenmannia virescens and Eigenmannia sp.2, respectively. While X and Y paint probes hybridized to species-specific sex chromosomes, in reciprocal cross-FISH both probes hybridized exclusively to autosomes. The result suggests multiple independent origins of the XY systems in the analyzed populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cytogenetics
  • DNA Primers / genetics
  • Female
  • Gymnotiformes / classification
  • Gymnotiformes / genetics*
  • In Situ Hybridization, Fluorescence
  • Karyotyping
  • Male
  • Polymerase Chain Reaction
  • Sex Chromosomes / genetics*
  • Species Specificity


  • DNA Primers