Satellite DNA sites in four species of the genus Astyanax (Teleostei, Characiformes)

Abstract

Cytogenetic data about satellite DNA distribution in four Astyanax species (Characidae) from the Paraitinga river, Paraíba do Sul river basin, Brazil, are presented. In order to characterize the constitutive heterochromatin, C-banding, chromomycin A 3 and DAPI fluorescence staining, as well as fluorescence in situ hybridization (FISH) with the satellite DNA As-51 probe were performed. A. scabripinnis and A. parahybae presented 2n = 50 and 2n = 48 chromosomes, respectively. The heterochromatin was located in the pericentromeric and terminal regions of many chromosomes, corresponding to GC-positive regions and to the As-51 satellite DNA in terminal regions. A. intermedius and A. giton, both with 2n = 50 chromosomes, showed little heterochromatin, mostly restricted to the terminal and pericentromeric regions of a few chromosomes. No GC-positive regions, neither any correspondence between the scarce heterochromatin of these species and the As-51 satellite DNA was observed. AT-positive blocks were not detected in any of the species studied. Based on these and other available data, the hypothesis that Astyanax represents a polyphyletic group is discussed.

Chromosomal Mapping of Repetitive DNA and Cytochrome C Oxidase I Sequence Analysis Reveal Differentiation among Sympatric Samples of <b><i>Astyanax</i></b><b><i>fasciatus</i></b> (Characiformes, Characidae)

“…costal drainages, upper Tietê River) present few As51 DNA sites, while individuals found in inland basins (e.g. Paranapanema and Mogi-Guaçu river) may present several sites [Abel et al, 2006;Kavalco et al, 2007Kavalco et al, , 2011Kavalco et al, , 2013Pazza et al, 2008]. Although we have not mapped the As51 DNA in the present study, the heterochromatin distribution patterns found are very similar to those presented in Kavalco et al [2013] in specimens collected at Salesópolis, SP (upper Tietê River), confirming the proposed scenario.…”

Trends in Karyotype Evolution in Astyanax (Teleostei, Characiformes, Characidae): Insights From Molecular Data

“…In relation to rDNA 5S, most of the species/populations already analyzed have the same following pattern: one site on the marker chromosome plus a pair of acrocentric chromosomes with a rDNA 5S site in the proximal region; this was also observed in the specimens analyzed in the present work ( Kavalco et al, 2004 , 2007 , 2009 , 2016 ; Pazza et al, 2006 ) and in the literature available for A. bockmanni , A. fasciatus , and A. parahybae ( Almeida-Toledo et al, 2002 ; Hashimoto et al, 2011 ; Silva et al, 2013 ; Daniel et al, 2015 ). Despite this relatively conserved pattern, there are two autapomorphies in the 5S rDNA phenotype in A. fasciatus .…”

“…These other species are less studied by cytogenetic methods, but until now, the chromosome characteristics seems to be shared ( Mendes et al, 2011 ; Coutinho-Sanches and Dergam, 2015 ), bringing new evidence supporting the group. Unfortunately, As51 repetitive DNA in these coastal distribution species has not been confirmed so far ( Kavalco et al, 2007 , 2009 ).…”

Molecular cytogenetics of Astyanax ribeirae (Teleostei, Characidae), an endemic characin of the Atlantic rainforest

“…There are certain groups characterized by large amounts of heterochromatin at terminal position [21,26], that enable to determine cases of both inter-and intraindividual polymorphism [16,17]. On the other hand, these conspicuous blocks are absent in some other species [8,9,13,14,21], although all species share small C-bands at pericentromeric region and interspersed with NORs, similar to the pattern herein described for A. ribeirae (Fig. 2a).…”

“…2a). Data about the inter-specific homology of a satellite DNA isolated from A. scabripinnis carrying sequences similar to transposable elements [19] have shown that such DNA sequence was quite dispersed in some species, like in the A. scabripinnis and A. fasciatus groups [1,17,26], but is absent in coastal species, like A. giton, A. intermedius and A. hastatus [9,13].…”