透過基因組分析揭示泰國金馬鱗魚 （Tor tambra）的性別相關區域

Abstract

none

The Thai, or Javan, mahseer (Tor tambra) is a freshwater cyprinid of ecological and economic significance, yet its genomic architecture and mechanisms of sex determination remain poorly understood. This study presents the first long-read only genome assembly for T. tambra using Oxford Nanopore sequencing, revealing indications of a fourth round of whole genome duplication based on genome metrics and Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness. Sex-specific genomic regions were investigated through both k-mer–based and allele frequency–based approaches, with findings supporting an XX/XY sex determination system. A high number of male-specific 60-mers enabled the assembly of putative male-linked contigs. BLASTn analysis of sex-specific contigs uncovered several predicted genes potentially related to development or sex differentiation; however, the absence of canonical sex-determining genes and limited query coverage suggest that these findings should be interpreted with caution. Allele frequency analysis further identified six male-associated scaffolds, suggesting putative Y-linked regions. This study also demonstrates the importance of selecting appropriate k-mer lengths for marker discovery. While the findings provide initial insights into sex-linked genomic features in T. tambra, the exact localization of sex-determining loci remains unresolved. Overall, this research offers a genomic foundation for future studies on sex determination and genome evolution in T. tambra, with potential applications in aquaculture, including non-invasive sex identification and selective breeding strategies.