Characterization of eukaryotic biodiversity of the Laje de Santos using 18s rRNA

• Grant number: 23/12613-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2024
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Rodrigo Rodrigues Domingues
• Grantee: Julia Silva Antonio
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/10201-0 - Marine biodiversity: an exploration of São Paulo coastal islands using environmental DNA metabarcoding, AP.BTA.JP

Abstract

"Understanding biodiversity associated with specific ecosystems is essential for comprehending biogeographic patterns and, above all, for developing strategies for the analysis, prevention, and mitigation of potential ecological imbalances. This aspect has gained increasing importance in the marine environment in recent years due to the rise in human activities and influences in this environment, resulting in significant changes in the number of species and individuals inhabiting certain regions. This is due, for example, to fishing, the irregular discharge of industrial waste, and the introduction of invasive species, which, in turn, destabilize the harmonious ecological relationships among different trophic levels present in the ecosystem. In this context, molecular methods for biota analysis stand out as viable and effective alternatives for studying biodiversity in various marine ecosystems. The metabarcoding technique enables the identification of different species of organisms present in a particular location by analyzing different genomic regions (e.g., 18S, 12S, COI) of genetic material extracted from an environmental sample. However, one of the crucial aspects of metabarcoding efficiency is the use of genomic regions capable of distinguishing a range of species and the use of specific primers for a particular group, capable of detecting as many species as possible while minimizing the occurrence of false positives and/or negatives, which can directly affect the analysis results. The combined use of molecular markers COI and 18S is among the most commonly used in faunal surveys in marine environments, as they provide a more comprehensive and precise understanding of biodiversity. COI is often used for species-level identification, particularly useful for distinguishing closely related species. On the other hand, 18S rRNA is more conserved, making it more suitable for studying relationships at higher taxonomic levels. Therefore, combining both markers allows for the capture of a broader range of taxonomic information. Thus, this project aims to standardize the use of the 18S marker for marine biodiversity assessment in one of the areas with the highest species diversity on the Brazilian coast."