Marsílio S P Rocha, Gideão W W F Costa, Marcelo B Cioffi, Luiz A C Bertollo, Vanessa C S Oliveira, Karlla D J Amorim, Wagner F Molina
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引用次数: 0
Abstract
Background: The damselfishes, an extremely diverse group of herbivorous fish, stands out as an important and ubiquitous ecological component of coral reefs. In the Western South Atlantic, the genus Stegastes is the most representative, whose evolutionary paths and taxonomic status of insular endemic species have been better evaluated. To clarify the karyotypic evolution involved in the diversification of this group, cytogenetic analyses were performed in four nominal species (S. variabilis and S. fuscus, distributed in Brazilian coastal regions; S. rocasensis and S. sanctipauli, from Rocas Atoll and São Paulo and São Pedro Archipelago) and one subspecies (S. fuscus trindadensis, from Trindade and Martim Vaz Archipelago).
Results: Classical cytogenetic protocols and fluorescence in situ hybridization (FISH) with 18S and 5S rDNA probes, were used for comparative analyses. All species had 2n=48 chromosomes, with high FN values ranging from 88 to 92. Stegastes rocasensis and S. sanctipauli shared identical cytogenetic patterns, while S. f. trindadensis revealed a syntenic arrangement of 18S and 5S rDNA sites not found in S. fuscus from the Brazilian coast.
Conclusion: The karyotypic evolution of Stegastes was predominantly driven by multiple pericentric inversions (and/or centromere shifts), resulting in changes in the internal organization of chromosomes. Stegastes rocasensis and S. sanctipauli have similar cytogenetical patterns, as well as S. fuscus and S. f. trindadensis indicating incipient evolutionary differentiation in insular species. Mapping other repetitive DNA sequences provided an exceptional opportunity to clarify chromosomal changes and their association with the evolutionary diversification of Stegastes species.
期刊介绍:
During the last decades, ''Cytogenetic and Genome Research'' has been the leading forum for original reports and reviews in human and animal cytogenetics, including molecular, clinical and comparative cytogenetics. In recent years, most of its papers have centered on genome research, including gene cloning and sequencing, gene mapping, gene regulation and expression, cancer genetics, comparative genetics, gene linkage and related areas. The journal also publishes key papers on chromosome aberrations in somatic, meiotic and malignant cells. Its scope has expanded to include studies on invertebrate and plant cytogenetics and genomics. Also featured are the vast majority of the reports of the International Workshops on Human Chromosome Mapping, the reports of international human and animal chromosome nomenclature committees, and proceedings of the American and European cytogenetic conferences and other events. In addition to regular issues, the journal has been publishing since 2002 a series of topical issues on a broad variety of themes from cytogenetic and genome research.