Genetic basis of adaptive traits in South American Arowanas

• Grant number: 24/15521-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Marcelo de Bello Cioffi
• Grantee: Fernando Henrique Santos de Souza
• Supervisor: Zuzana Musilova
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Charles University in Prague (CU), Czech Republic
• Associated to the scholarship: 21/11169-2 - Transcriptomics and molecular evolution of genes associated with adaptation in arowanas (Osteoglossiformes, Osteoglossidae)., BP.DR

Abstract

Understanding the genetic basis of adaptive traits is a key step to understanding adaptation, and the evolutionary process. Traits such as vision and color are excellent subjects for investigating adaptation, as they can directly impact an individual's ability to survive and reproduce. In South America, the two extant Osteoglossum species (Arowanas) offer a significant model for studying these characteristics as these species exhibit distinct coloration and predominantly inhabit different aquatic environments. In the student Ph.D. main project, integrative transcriptomics, molecular evolution, and genomic approaches are being applied to understand the molecular basis of their phenotype and visual system and the evolutionary implications of their adaptive divergence. Up to now, skin and scales transcriptomes were already assembled for both arowana species. Analysis of initial annotations, orthologs, and differential expression revealed 1,064 differentially expressed genes, with several of them being linked melanin production pathway. In Profa. Dra. Zuzana Musilová's laboratory, a global reference on fish sensory genetics, this BEPE project will undertake retina RNA-Seq and other bioinformatic analysis to investigate Osteoglossum opsin repertoire, differential expression, and selection. We will characterize the opsin repertoire of both Osteoglossum species, assemble species-specific transcriptomes, identify differentially expressed genes, search for selection, and undertake retina-FISH studies. The retina results will be coupled with color results searching for evidence of correlated evolution and their potential roles as adaptive elements in the colonization of new environments. Nonetheless, the project will allow the scientific training and development of the student, to interact with a worldwide renowned scientific group, and learn relevant techniques currently employed by Dra. Musilová's research group.