design: For Hi-C library preparation, we used cells from coelomic fluid and protocol of Lafontaine (https://doi.org/10.1002/cpz1.198) with some modifications for easier and faster operations. MboI (R0147, NEB) and biotin-14-dATP (19524016, Thermo Fisher Scientific) were used for chromatin digestion and biotinylation of DNA ends. Chromosome conformation-captured DNA (3 ug) was prepared for sequencing on DNBSEQ-G50 in the PE160 mode with a MGIEasy Universal DNA Library Prep Kit and NEBNext dsDNA Fragmentase.