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

• Published in: Cytogenetic and genome research Vol. 121; no. 1; pp. 55 - 58
• Main Authors: Henning, F., Trifonov, V., Ferguson-Smith, M.A., de Almeida-Toledo, L.F.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2008
• Subjects: Animals; Base Sequence; Cytogenetics; DNA Primers - genetics; Eigenmannia; Eigenmannia virescens; Female; Freshwater; Gymnotiformes; Gymnotiformes - classification; Gymnotiformes - genetics; In Situ Hybridization, Fluorescence; Karyotyping; Male; Original Article; Polymerase Chain Reaction; Sex Chromosomes - genetics; Species Specificity; Teleostei
• ISSN: 1424-8581; 1424-859X
• DOI: 10.1159/000124382

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.