Nematode genome announcement: A chromosome-scale genome assembly for the Pristionchus pacificus reference mapping strain PS1843.

Pristionchus pacificus is a free-living nematode that shares many features with Caenorhabditis elegans, such as its short generation time and hermaphroditism, but also exhibits novel traits, i.e., a mouth-form dimorphism that enables predation. The availability of various genetic tools and genomic resources make it a powerful model organism for comparative studies. Here, we present an updated genome of the P. pacificus strain PS1843 (Washington) that is most widely used for genetic analysis. Assembly of PacBio reads together with reference-guided scaffolding resulted in a chromosome-scale genome spanning 171Mb for the PS1843 strain. Whole genome alignments between the P. pacificus PS1843 genome and the genome of the P. pacificus reference strain PS312 (California) revealed megabase-sized regions on chromosomes III, IV, and X that explain the majority of genome size difference between both strains. The improved PS1843 genome will be useful for future forward genetic studies and evolutionary genomic comparisons at the intra-species level.