Chromosomal studies on color variants of Asian arowana Scleropages formosus (Teleostei, Osteoglossiformes)

Abstract

The species Scleropages formosus (Asian arowana) is one of the most expensive ornamental fish species in the market and, due to this fact; it has been widely exploited in its natural habitats being now listed as one of the species with one of the highest risk of extinction. However, little information is known about its genome organization. Unlike the other arowana species already described, the Asian Arowana has at least five naturally known color variants. They all appear to have originated from different regions of Southeast Asia, probably connected by freshwater habitats during the Pleistocene ice ages. However, the taxonomic nature of these variant forms is not yet fully understood and there are doubts as to the status of these variants as representative of one or several species. Thus, this project intends to analyze 05 color variants (Green, Silver, Gold Crossback, High back Golden and Super Red) of the species S. formosus using conventional (Giemsa staining and C-banding) and molecular cytogenetics [ rDNA, Microsatellites, Comparative Genomic Hybridization (CGH) and Chromosome Painting (WCP)] experiments in order to verify whether there is a differentiation between them at the chromosome level that supports the separation of these variants into distinct species.