An integrative approach for the analysis of dispersal, adaptive and evolutionary processes between realted species with intercontinental distribution: the Osteoglossidae family (Teleostei, Osteoglossiformes) as an investigative model: part IV

Abstract

This project will continue the evolutionary analysis, which has been addressed in our previous projects approved by FAPESP. In this sense, problems that still need to be better understood will be addressed, covering biogeographic and species dispersion issues between different continents, the colonization routes, as well as the evolutionary consequences resulting from geographical isolation and adaptation to new colonized environments. The order Osteoglossiformes is an excellent study material, since this primitive group of teleost fishes, that although restricted to freshwater environments, is currently dispersed in different continents. Representatives of the Osteoglossidae family will be particularly investigated, considering their relevance to the proposed objectives. Popularly known as arowana, osteoglossids are one of the most emblematic groups of Osteoglossiformes, today distributed in different countries of the Old and New Worlds. They stand out for their beauty and exuberance of the color pattern, which allows them to reach very high figures in the aquarium trade. In Brazil, particularly in the Amazon region, two endemic species occur, the silver arowana (Osteoglossum bicirrhossum) and the black arowana (Osteoglossum ferrerai), while in the Asian region there are distinct strains of Scleropages formosus, differentiated by the diversity of their color pattern. Therefore, this group offers a unique opportunity for investigations of genes that may be undergoing a process of rapid evolution and natural selection, allowing for successful colonization in new environments and understanding how genome can favor adaptive responses. At the same time, the biogeographic reconstruction of the diversification of this family, with tests of hypotheses that potentially explain the close phylogenetic relationship of species distributed in different continents, will enable the understanding of the dispersive process that occurred in this group. The effect of continental drift will be assessed and compared with other hypotheses that explain the diversification patterns currently observed. Finally, cytogenetic analyzes coupled with species delimitation models will be performed on 05 color variants of Scleropages formosus (the Asian arowana), looking for robust subsidies, at the chromosomal and genomic level, that can characterize the separation of these variants in different species, an issue that still remains open in that group. Integrative approaches of molecular cytogenetics, biogeography, genomics, and transcriptomics will be used, providing a more robust basis to the proposals presented. Joining this project is a team composed of 09 national and international research groups, adding efforts to make it feasible, thus allowing the proposed objectives to be achieved. (AU)