Biogeographic analysis of the shark Squalus cubensis (Chondrichthyes: Squaliformes) in the Atlantic Ocean, based on genetic markers

• Grant number: 19/15148-0
• Support type: Scholarships in Brazil - Master
• Effective date (Start): June 01, 2020
• Effective date (End): July 31, 2021
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal researcher: Fausto Foresti
• Grantee: Aisni Mayumi Corrêa de Lima Adachi
• Home Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Overfishing imposes changes in the life strategy of the populations of organisms, especially in relation to sharks and rays, organisms that make up the group of elasmobranchs. Thus, understanding the structure of populations becomes an important tool for conservation and management of stocks and requires a broad knowledge on genetic, biogeographic, and distribution and occurrence of species. The identification of stocks genetically differentiated and adapted to their habitat represent a fundamental point for the management of the species. Sharks of the genus Squalus (family Squalidae) are currently made up of 26 species and are popularly called spiny dogfish sharks. This genus constitutes one of the most problematic groups of sharks taxonomically due to the great morphological similarity among the species and, thus, many researchers believe that in this group there are erroneously described taxa. In the Atlantic Ocean there are about 11 species of the genus Squalus; however, in the Brazilian coast these species were never genetically identified or had their populations analyzed. Data scarcity and taxonomic confusion reflect the current status of these organisms, with their listing on the IUCN (International Union for Conservation of Nature) red list in which most Squalus species are listed as "insufficient data" or "nonexistent". In this context, the main objective of this work is to use the genetic tool of DNA barcoding to identify the species of sharks of the S. cubensis that occur in the Atlantic Ocean, as well as to develop SNPs (Single Nucleotide Polymorphisms) markers for population studies of the identified species. In order to carry out this research, we obtained 110 samples of S. cubensis colected from different locations on the coast of Brazil. DNA extraction, COI (DNA barcoding) amplification, SNPs identification and analysis of second generation sequencing (Genotyping by Sequencing: GBS) will be performed in order to test hypotheses of relationships between species and populations, including isolation biogeographic barrier. It is considered that such informations will contribute to the knowledge of the diversity of this group and to the orientation in conservation programs of Atlantic spiny dogfish sharks. (AU)