title: Whole chromosome painting reveals independent origin of sex chromosomes in closely related forms of a fish species.
abstract: The wolf fish Hoplias malabaricus includes well differentiated sex systems (XY and X(1)X(2)Y in karyomorphs B and D, respectively), a nascent XY pair (karyomorph C) and not recognized sex chromosomes (karyomorph A). We performed the evolutionary analysis of these sex chromosomes, using two X chromosome-specific probes derived by microdissection from the XY and X(1)X(2)Y sex systems. A putative-sex pair in karyomorph A was identified, from which the differentiated XY system was evolved, as well as the clearly evolutionary relationship between the nascent XY system and the origin of the multiple X(1)X(2)Y chromosomes. The lack of recognizable signals on the sex chromosomes after the reciprocal cross-FISH experiments highlighted that they evolved independently from non-homologous autosomal pairs. It is noteworthy that these distinct pathways occur inside the same nominal species, thus exposing the high plasticity of sex chromosome evolution in lower vertebrates. Possible mechanisms underlying this sex determination liability are also discussed.
authors.affiliation: Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil. mbcioffi@ufscar.br
authors.forename: Marcelo
authors.initials: M
authors.lastname: de Bello Cioffi
authors.forename: Antonio
authors.initials: A
authors.lastname: Sánchez
authors.forename: Juan Alberto
authors.initials: JA
authors.lastname: Marchal
authors.forename: Nadezda
authors.initials: N
authors.lastname: Kosyakova
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
authors.forename: Vladimir
authors.initials: V
authors.lastname: Trifonov
authors.forename: Luiz Antonio Carlos
authors.initials: LA
authors.lastname: Bertollo
mesh_terms: D000818:Animals; D060125:Characiformes / Q000235:genetics*; D020223:Chromosome Painting; D019143:Evolution, Molecular; D005260:Female; D008297:Male; D042282:Microdissection; D010802:Phylogeny; D012730:Sex Chromosomes / Q000235:genetics*