Molecular composition and evolution of supranumerary chromosome in Astyanax paranae (Characiformes, Characidae)

• Grant number: 13/08865-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: September 15, 2013
• End date: October 14, 2013
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Fausto Foresti
• Grantee: Duílio Mazzoni Zerbinato de Andrade Silva
• Supervisor: Juan Pedro Martínez Camacho
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: Universidad de Granada (UGR), Spain
• Associated to the scholarship: 11/16825-3 - Molecular and cytogenetic structure of B-chromosomes in Astyanax paranae (Characiformes, Characidae), BP.MS

Abstract

B chromosomes are extra genomic elements to the standard chromosome complement and occur in many organisms. They may have different origins, including derivation of autosomes or sex chromosomes and even as a result of interspecific crosses. The molecular mechanisms that drive the evolution of these segments resemble those of univalent sex chromosomes and may involve gene silencing, heterochromatinization processes, accumulation of repetitive DNA and transposons. The recent advent of more resolutive cytogenetic techniques, such as microdissection, method that allows the direct isolation of DNA from any chromosomal region associated with the technique of in situ hybridization with fluorescent dyes has provided advancements in the understanding of the structure and composition of genomic elements in a significant number of chromosomes carrying organisms B. Thus, this project will be based on the microdissection of B chromosomes found in cells of Astyanax paranae, collected at Botucatu-SP, as well as genomic DNA extraction and PCR amplification of several repetitive DNA sequences (45S and 5S rDNA, and genes for histones H1, H3 and H4), and retrotransposable elements (Rex1, and Rex3 Rex6) in both types of extracted DNA (gDNA and ¼B-DNA). The development of this work will allow an overview of the relationship of the B chromosomes with the A complement. Finally, this study will contribute to the knowledge of the molecular content of B chromosomes in a species of Astyanax and generate information to clarify aspects of the origin of this type of DNA segment in the genome of the genus. (AU)