A chromosome-level genome assembly of the classical model nematode Panagrellus redivivus for comparative studies of parasitism evolution

Abstract

Panagrellus redivivus is a free-living nematode that served as an early model system for nematode biology prior to Caenorhabditis elegans. As a member of Clade IV, a clade harboring major plant-parasitic (e.g., Bursaphelenchus xylophilus) and animal-parasitic (e.g., Strongyloides spp.) species, P. redivivus represents a crucial, phylogenetically proximate non-parasitic reference for investigating the evolution of parasitism. Here, we present a chromosome-level genome assembly of P. redivivus constructed using Oxford Nanopore long reads, Illumina short reads, and Hi-C scaffolding. The assembly is resolved into five chromosome-scale scaffolds, with completeness validated by Hi-C contact maps and the identification of a non-canonical telomeric repeat motif. The assembly demonstrates high gene-space completeness (97.1% BUSCO) and contains 17,839 predicted protein-coding genes. Comparative orthology analysis revealed extensive orthogroup sharing between P. redivivus and Clade IV parasites, enabling comparative evolutionary studies with reduced confounding effects from deep lineage divergence. This high-quality genome provides a key resource for investigating the genetic basis of distinctive biological traits, including ovoviviparity, as well as gene family dynamics and parasite evolution.