An intercontinental approach of the chromosomal evolution in the order osteoglossiformes (Teleostei: osteoglossomorpha)

Abstract

Freshwater fishes represent an important model for biogeographic studies considering that they do not disperse easily and, therefore, each continent presents a particular freshwater fish fauna. The Osteoglossiformes represent one of the most primitive groups of Teleosts and has at least one representative in all continents of the southern hemisphere, with the exception of Antarctica, being, therefore, an important model for biogeographical studies. Such widely distribution may have contributed to the huge diversity found in this group, perhaps due to the need of the species to adapt to different environments where they naturally occur. It is, therefore, a group of great scientific and economical interest considering its wide use in human consumption as well as the hobbyist trade with exotic species of great commercial value. However, cytogenetic studies in Osteoglossiformes are still scarce and basically restricted, with few exceptions, to the description of the chromosomal number of a small number of species, justifying the need for a deeply chromosomal analysis to be performed in more species, in order to clarify the evolutionary processes occurred in this group. In this way, our proposal includes the chromosomal investigation of species from the order Osteoglossiformes, representatives from distinct intercontinental regions, with a network of international collaborators also interested in this promising approach. As a first step, species from 03 of the 06 families of the order Osteoglossiformes, belonging to the Pantodontidae, Notopteridae and Arapaimidae families will be analyzed through Conventional (C banding and giemsa staining) and Molecular Cytogenetics analysis, the last one including the chromosomal mapping of different repetitive DNA sequences as markers, in order to investigate the evolutionary events associated with the chromosomal diversification in this group and also contribute with valuable phylogenetic subsidies. Allied to this project there is a team of researchers from 04 different countries, including Brazil, joining efforts to research what is being proposed, thus enabling a broad evolutionary cytogenetics approach in the order Osteoglossiformes, portraying their organization, genomic diversification and its biodiversity. (AU)