Development of genetic markers to sex identification of Astatotilapia latifasciata

• Grant number: 18/25350-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2019
• End date: September 30, 2020
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Adauto Lima Cardoso
• Grantee: João Pedro Silva Climaco
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 15/16661-1 - Sex and B chromosome enigmas: model systems for the study of chromosome and genome evolution, AP.TEM

Abstract

Sexual determination acts on most species of fish by means of effective genes or a group of genes distributed on sex chromosomes or autosomes. Then, in spite of the great variety of sexual determination systems present among fish, there is still a large percentage of species in which the sex chromosomes are not totally differentiated, preventing a sex identification by classical techniques of cytogenetics, including fluorescence in situ hybridization (FISH). In addition, sexual dimorphism itself, especially with regard to secondary sexual characteristics that influence the social interaction of individuals of the same species, such as the dichromatism present in cichlid species, may suffer external influences and become virtually non-existent, such as occurs between males disputing for a female or for territory. For this reason, not only the karyotype but also the external morphology of species with these characteristics may be limiting on sexual identification. In the African cichlid Astatotilapia latifasciata (2n = 44, or 2n = 44 + 1B, or 2n = 44 + 2B) no heteromorphic sex chromosomes were found, which, together with the low reliability of the dichromatism of this species, avoid valid sexual identification. Based on these data and in other studies that have already been successful in the search for molecular markers for sex in the genome of several cichlid species, the objective of this project is to identify, analyze and validate sex-specific DNA sequences that allow the identification of Astatotilapia latifasciata. For this, genomes of A. latifasciata males and females, previously sequenced by the HiSeq platform (Illumina), using in silico methods and molecular biology techniques will be explored. It is hoped that the development of this project will aid in the sexual identification in this species, making possible the exploration of the complex mechanism of sexual determination in cichlids and several other questions about the biology of this species.