Atlantic moonfishes: independent pathways of karyotypic and morphological differentiation
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ORIGINAL ARTICLE
Atlantic moonfishes: independent pathways of karyotypic and morphological differentiation Uedson Pereira Jacobina • Marcelo Ricardo Vicari • Pablo Ariel Martinez • Marcelo de Bello Cioffi • Luiz Antonio Carlos Bertollo • Wagner Franco Molina
Received: 6 June 2012 / Revised: 27 October 2012 / Accepted: 1 November 2012 Ó Springer-Verlag Berlin Heidelberg and AWI 2012
Abstract Fish of the genus Selene, known as lookdowns or moonfish, are one of the most morphologically derived groups of the family Carangidae, whose phylogenetic relationships are still largely unknown. In this study, we discuss karyoevolutionary aspects of three representatives of this genus from the Western Atlantic: Selene brownii (2n = 48; FN = 48), Selene setapinnis (2n = 46; FN = 48), and Selene vomer (2n = 48; FN = 50). Their body patterns were also investigated and compared to one another and in relation to two other species of different genera. Two mechanisms of karyotypic evolution seem to have acted in the diversification of this genus, namely pericentric inversions and centric fusions. Mapping of rDNA sequences showed that chromosome pairs bearing 5S rDNA sites are similar, whereas those bearing 18 rDNA sites are morphologically distinct while apparently also exhibiting interspecies synteny. Although the nucleolar organizer-bearing chromosomes are extremely efficient cytotaxonomic markers among Selene species, others Communicated by H.-D. Franke. U. P. Jacobina (&) P. A. Martinez W. F. Molina Departamento de Biologia Celular e Gene´tica, Centro de Biocieˆncias, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil e-mail: [email protected] M. R. Vicari Laborato´rio de Citogene´tica e Evoluc¸a˜o, Departamento de Biologia Estrutural, Molecular e Gene´tica, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil M. de Bello Cioffi L. A. C. Bertollo Departamento de Gene´tica e Evoluc¸a˜o, Centro de Cieˆncias Biolo´gicas e da Sau´de, Universidade Federal de Sa˜o Carlos, Sa˜o Carlos, SP, Brazil
cytogenetic patterns of these species are relatively conserved. Hybridization with telomeric probes (TTAGGG)n did not exhibit interstitial telomeric sites (ITS), especially in S. setapinnis, where, along with a reduction in diploid number, a large metacentric pair derived from centric fusion is present. Data obtained by geometric morphometrics enable a clear morphological distinction among the three species, as well as in relation to two other species of the genus Caranx and Oligoplites. Data obtained suggest that morphologic evolution in Selene species was primarily dissociated from visible changes that occurred at the chromosomal level. Keywords Selene Pericentric inversions Centric fusion Morphological divergence
Introduction Fish of the genus Selene, known as lookdowns or moonfish, belong to one of the most morphologically derived groups compared to the 32 genera that make up the family Carangidae. Indeed, they exhibit a tall round body, laterally compressed, with a unique steep head (Smith-Vaniz 1979
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