Chromosomal differentiation and speciation in sister-species of Grammatidae (Perciformes) from the Western Atlantic

In the tropical Atlantic, the ichthyofauna between the coast of Brazil and the Caribbean regions, divided by the Amazon barrier, is very similar presenting several geminate species, including Gramma brasiliensis, endemic in Brazil, and its Caribbean counterpart Gramma loreto. Morphological and molec...

Full description

Saved in:
Bibliographic Details
Published in:Helgoland marine research 2012-09, Vol.66 (3), p.363-370
Main Authors: Molina, Wagner Franco, da Costa, Gideão Wagner Werneck Felix, de Bello Cioffi, Marcelo, Bertollo, Luiz Antonio Carlos
Format: Article
Language:English
Subjects:
allopatry
Animal populations
Chromosomes
diploidy
Fish
fluorescence in situ hybridization
Genetic markers
Gramma
Gramma brasiliensis
Gramma dejongi
Gramma linki
Gramma loreto
Gramma melacara
Grammatidae
habitats
heterochromatin
karyotyping
Marine
Perciformes
Population genetics
ribosomal DNA
silver nitrate
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In the tropical Atlantic, the ichthyofauna between the coast of Brazil and the Caribbean regions, divided by the Amazon barrier, is very similar presenting several geminate species, including Gramma brasiliensis, endemic in Brazil, and its Caribbean counterpart Gramma loreto. Morphological and molecular studies have helped establish evolutionary patterns that sister-species of these two marine habitats are subjected to. However, their chromosomal characteristics are only beginning to be better characterized. Accordingly, a comparative cytogenetic analysis was carried out in G. brasiliensis and G. loreto, seeking evidence of cytotaxonomic markers implicated in the karyotypic diversification of these species and likely associated with speciation events. Heterochromatic regions and their affinity to fluorochromes GC- or AT-specific were identified, as well as the distribution of ribosomal DNA sites in chromosomes, either by silver nitrate impregnation (Ag-NORs) or dual-color FISH mapping with 18S and 5S rDNA probes. While displaying the same diploid number, 2n = 48 chromosomes, considered basal for Perciformes, the two species differed in karyotype structure, showing karyotypic formulas and species-specific heterochromatin pattern. The cytological characters found support the differentiating status of these species, possibly achieved under the conditions of allopatry due to the Amazon/Orinoco barrier, showing chromosomal peculiarities in Grammatidae species when compared to other groups of Perciformes.
ISSN:1438-387X
1438-3888
DOI:10.1007/s10152-011-0276-x