The chromosome-level genome assembly of the red swamp crayfish Procambarus clarkii.

Red swamp crayfish, Procambarus clarkii, is the most cultured freshwater crayfish species. It attracts significant research attention due to its considerable economic importance. However, the limited availability of genome information has impeded further genetic studies and breeding programs. By utilizing Illumina, PacBio, and Hi-C sequencing technologies, we present a more comprehensive and continuous chromosome-level assembly for P. clarkii than the published one. The final genome size is 4.03 Gb, consisting of 2,358 scaffolds with a N50 of 42.87 Mb. Notably, 3.68 Gb, corresponding to 91.42% of the genome, was anchored to 94 chromosomes. The assembly comprises 70.64% repetitive sequences, including 5.21% tandem repeats and 65.40% transposable elements. Additionally, a total of 4,456 non-coding RNAs and 28,852 protein-coding genes were predicted in the P. clarkii genome, with 96.26% of the genes were annotated. This high-quality genome assembly not only represents a significant improvement for the genome of P. clarkii and provides insights into the unique genome evolution, but also offers valuable information for developing freshwater aquaculture and accelerating genetic breeding.