Chromosome-level genome assembly of the sponge Halisarca dujardinii.

Halisarca dujardinii is a marine sponge known for its ability to completely regenerate via cell reaggregation. Here we present the first chromosome-level genome assembly of H. dujardinii, generated using Oxford Nanopore long reads, Illumina short reads, and Hi-C data. The final assembly spans 226.5 Mbp and is organized into 21 chromosome-scale scaffolds, representing the full nuclear genome, with an assembly N50 of 10.1 Mbp. In addition, we report the complete mitochondrial genome for H. dujardinii, assembled as a circular molecule and annotated to contain 14 protein-coding genes. We provide a comprehensive genome annotation comprising 14,565 nuclear protein-coding genes, of which 85.6% are functionally annotated, along with repetitive elements and non-coding RNAs. Transcript models were refined using extensive bulk and single-cell RNA sequencing data, enabling accurate annotation of 3' untranslated regions. This new genomic resource provides a valuable foundation for investigating the molecular basis of sponge regeneration, as well as for comparative studies of sponge evolution and marine biology.