Secrets of the Goo: The genome assembly of the Pacific banana slug, Ariolimax columbianus.

The Pacific banana slug, Ariolimax columbianus, is endemic to the forests of the Pacific Northern West. Found throughout the coastal foothills and mountains of California, the hermaphroditic molluscs Ariolimax spp. are niche-constrained, hyper-localized, and phenotypically diverse. The evolutionary history, recent population history and environmental conditions leading to their phenotypic and genetic variation are not understood. To facilitate such research, we present the first high-quality de novo genome assembly of A. columbianus as part of the California Conservation Genomics Project. Pacific Biosciences HiFi long reads and Omni-C chromatin-proximity sequencing technologies were used to produce a de novo genome assembly, consistent with the standard California Conservation Genomics Project genome assembly protocol. This assembly comprises 401 scaffolds spanning 2.29 Gb, represented by a scaffold N50 of 94.9 Mb, a contig N50 of 3.7 Mb, and a benchmarking universal single-copy ortholog completeness score of 93.9%. Future work will use the A. columbianus genome to study the population structure of Ariolimax spp. across California to understand patterns of population structure, genetic diversity, and the broader ecological connections with their habitat. This data will contribute to the California Conservation Genomics Project, expanding the knowledge about the partitioning of genomic variation across the different ecoregions of California.