title: Laser microdissection-based analysis of the Y sex chromosome of the Antarctic fish Chionodracohamatus (Notothenioidei, Channichthyidae).
abstract: Microdissection, DOP-PCR amplification and microcloning were used to study the large Y chromosome of Chionodracohamatus, an Antarctic fish belonging to the Notothenioidei, the dominant component of the Southern Ocean fauna. The species has evolved a multiple sex chromosome system with digametic males showing an X1YX2 karyotype and females an X1X1X2X2 karyotype. Fluorescence in situ hybridization, performed with a painting probe made from microdissected Y chromosomes, allowed a deeper insight on the chromosomal rearrangement, which underpinned the fusion event that generated the Y. Then, we used a DNA library established by microdissection and microcloning of the whole Y chromosome of Chionodracohamatus for searching sex-linked sequences. One clone provided preliminary information on the presence on the Y chromosome of the CHD1 gene homologue, which is sex-linked in birds but in no other vertebrates. Several clones from the Y-chromosome mini-library contained microsatellites and transposable elements, one of which mapped to the q arm putative fusion region of the Y chromosome. The findings confirm that interspersed repetitive sequences might have fostered chromosome rearrangements and the emergence of the Y chromosome in Chionodracohamatus. Detection of the CHD1 gene in the Y sex-determining region could be a classical example of convergent evolution in action.
authors.affiliation: Istituto di Bioscienze e Biorisorse, CNR, via P. Castellino 111, 80131 Napoli, Italy.
authors.forename: Ennio
authors.initials: E
authors.lastname: Cocca
authors.affiliation: Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy.
authors.forename: Agnese
authors.initials: A
authors.lastname: Petraccioli
authors.affiliation: Istituto di Bioscienze e Biorisorse, CNR, via P. Castellino 111, 80131 Napoli, Italy.
authors.forename: Maria Alessandra
authors.initials: MA
authors.lastname: Morescalchi
authors.affiliation: Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Odierna
authors.affiliation: Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Capriglione
keywords: Antarctic fish; CHD1 gene; Sex chromosomes