Identificação e análise de polimorfismos relacionados a genes de resistência a doença em tambaqui (Colossoma macropomum)

Abstract

Genetic diversity and immune adaptation are central components for the sustainability of aquaculture involving native species. In this study, 239 individuals of Colossoma macropomum (tambaqui) from different farmed subpopulations in Brazil were analyzed to identify and characterize single nucleotide polymorphisms (SNPs) associated with disease resistance-related genes. Using genotyping-by-sequencing (GBS), a total of 182,416 polymorphic SNPs were detected. Phylogenetic and principal component analyses (PCA) revealed a clear genetic structure among subpopulations, indicating a lack of recent gene flow and suggesting the influence of genetic drift and isolated reproductive management. High FST SNPs were identified in coding regions of functionally relevant genes such as unc5da, il16, epha2b, cd209, and rnf175, which are involved in key metabolic pathways including netrin signaling, T cell activation, Ephrin signaling, pathogen recognition, and antigen presentation via MHC I. Functional analysis of the mutations revealed the presence of synonymous, non-synonymous, and nonsense variants, indicating potential impacts on the structure and function of proteins involved in immune responses. These findings highlight candidate loci under natural selection and reinforce the potential of these variants as valuable markers in genetic improvement programs aimed at enhancing disease resistance. This study contributes to advancing the genomic knowledge of tambaqui and provides a foundation for the application of marker-assisted selection strategies in native species aquaculture.