Cytogenetic and Molecular Data Demonstrate that the Bryconinae Ostariophysi, Bryconidae Species from Southeastern Brazil Form a Phylogenetic and Phylogeographic UnitReportar como inadecuado




Cytogenetic and Molecular Data Demonstrate that the Bryconinae Ostariophysi, Bryconidae Species from Southeastern Brazil Form a Phylogenetic and Phylogeographic Unit - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Brycon spp. occur in Neotropical watersheds to the west and east of the Andes, and as they are sensitive to anthropogenic changes, many these species are endangered in southeastern Brazil. Coastal rivers in southeastern Brazil are characterized by the presence of relatively few freshwater fish species and high endemism of this fauna. The objective of this study was to examine whether Brycon spp. occurring in the coastal basins of southeastern Brazil are monophyletic, using cytogenetic data, mitochondrial, and nuclear molecular markers. All the species showed a diploid number of 50 chromosomes, a conserved number within the subfamily Bryconinae. However, the karyotypic formulas were unique to most species, including Brycon devillei 26m+22sm+2st, Brycon ferox 26m+12sm+12st, Brycon insignis 22m+20sm+8st, Brycon opalinus, and Brycon vermelha 24m+20sm+6st, indicating the prevalence of pericentric and paracentric inversions in the chromosomal evolution of these species. All of them had nucleolar organizer regions in the first pair of subtelocentric chromosomes and no equilocal distribution of heterochromatin in the first pair of chromosomes of the karyotype. These two features, not seen in any other Brycon spp. examined to date, indicate that Bryconinae species from the Brazilian southeastern coastal basins, including the monotypic genus Henochilus, are monophyletic. Also, this is the first study that reports NOR location and C-banding patterns as synapomorphies for a Neotropical fish species group. The monophyly was also supported by a phylogenetic analysis of 16S rDNA 16S, cytochrome oxidase subunit I COI, alpha-myosin MYH6 genes and S72 intron molecular data. Our results partially corroborate the -Brycon acuminatus- group proposed by Howes in 1982: our proposed clade keeps B. devillei, B. ferox, and B. insignis; but it also includes B. opalinus, B. vermelha, and H. weatlandii whereas it excludes B. nattereri. The phylogeographic unit formed by Bryconinae species in southeastern Brazil reflects the long and isolated paleohydrological history of these coastal basins relative to the continental watersheds.



Autor: Natália Martins Travenzoli, Priscilla Caroline Silva, Udson Santos, José Cola Zanuncio, Claudio Oliveira, Jorge Abdala Dergam

Fuente: http://plos.srce.hr/



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