!"#$%&'& ()& Genomic organization and comparative chromosome mapping of U1 snRNA gene in cichlid fish, with emphasis in Oreochromis niloticus* D.C. Cabral-de-Mello1,*, G.T. Valente2, R.T. Nakajima2 and C. Martins2 1UNESP – Univ Estadual Paulista, Instituto de Biociências/IB, Departamento de Biologia, Rio Claro, São Paulo, Brazil 2UNESP – Univ Estadual Paulista, Instituto de Biociências/IB, Departamento de Morfologia, Botucatu, São Paulo, Brazil Short running title: Genomic organization and mapping of U1 snRNA in cichlid fish * Corresponding author: UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Departamento de Biologia, CEP 18618-000 Botucatu, SP, Brazil Phone/Fax: 55 14 38116264. e-mail:
[email protected] *Cabral-de-Mello DC, Valente GT, Nakajima RT, Martins C (2012) Genomic organization and comparative chromosome mapping of the U1 snRNA gene in cichlid fish, with an emphasis in Oreochromis niloticus. Chromosome Research 20(2): 279-292. !"#$%&'& (*& Abstract To address the knowledge of genomic and chromosomal organization, and evolutionary patterns of U1 snRNA gene in cichlid fish this gene was cytogenetically mapped and comparatively analyzed in 19 species belonging to several clades of the group. Moreover, the genomic organization of U1 snRNA was analyzed using as reference the Oreochromis niloticus genome. The results indicated a high conservation of one chromosomal cluster of U1 snRNA in the African and Asian species with some level of variation mostly in the South American species. The genomic analysis of U1 revealed a distinct scenario of that observed under the cytogenetic mapping. It was observed just an enrichment of U1 gene in the linkage group (LG) 14, that do not correspond to the same chromosome that harbors the U1 cluster identified under the cytogenetic mapping.