The study of Neotropical fishes has expanded considerably in recent years, mainly due to the incorporation of new techniques for gathering and interpreting data. However, the relationship between many groups still needs better clarification and application of chromosome banding techniques, the use of fluorochrome-specific basis, using the methodology of phylogenetic analysis and in situ hybridization with fluorescent probes has been responsible for part of the expansion knowledge and understanding of evolutionary processes in Neotropical fishes. Accordingly, the development of specific probes such as histone and ribosomal genes, DNA consisting of moderate repeatability, the highly repetitive DNA (satellite DNA) and the advent of chromosome microdissection (method enabling the direct isolation of DNA from any region cytogenetically recognized), has enabled the hybridization of these markers in metaphase chromosomes by FISH technique called, allowing the mapping of genes on chromosomes and broadening the perspectives of analysis and study this group of vertebrates. This project is part of the general program of studies cytogenetics and molecular genetics of Neotropical fishes under development at the Laboratory of Biology and Genetics of Fishes (IBB / UNESP / BOTUCATU) and has as its main objective the cytogenetic analysis in a structural and molecular species and fish populations of the genus Trichomycterus that occur in different watersheds (T. iherengi - Tietê River; T. diabolus - Paranapanema; T. zonatus - Southeast Coastal Basin and T. cf. mimonha - Grande river basin). The work will be based on conventional cytogenetic analysis (Giemsa, NORs, banding C) and molecular, with ample physical mapping of DNA sequences, involving the application of fluorochromes specific bases and CMA3 DAPI, the location of genes 18S and 5S rDNA of telomeric sequences (TTAGGG) n, locating clusters for the protein histone H1, H3 and H4 and location of elements retrotransponíveis Rex1, and Rex3 Rex6. The development of this project will contribute information to identify the mechanisms connected to the diversification process within the chromosomal gender Trichomycterus, to the knowledge of chromosome structure and organization of some DNA sequences in the genome of the fish and also contribute information to aid in establishing the possible evolutionary and phylogenetic relationships among species and populations.
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