design: The Hi-C library was prepared from muscle tissue of a wild-caught Phoxinus grumi individual to capture the three-dimensional chromatin architecture. The experimental procedure was as follows: Fresh tissue was cross-linked with formaldehyde to fix intra-chromatin interactions. The cross-linked chromatin was then digested with a restriction enzyme. The resulting sticky ends were filled in with nucleotides including a biotinylated residue for marking the interaction junctions. The cross-linked DNA fragments were then ligated under dilute conditions to favor proximity ligation events, forming chimeric junctions representing original spatial contacts. After reversing the cross-links, the DNA was purified and sheared to a size of approximately 350 bp. The biotin-labeled fragments representing interaction products were captured using streptavidin beads. A standard Illumina sequencing library was then constructed from these enriched fragments through end-repair, A-tailing, and adapter ligation. Paired-end sequencing was subsequently performed on an Illumina NovaSeq PE 150 platform.