The genome of the Margined White butterfly (Pieris macdunnoughii): sex chromosome insights and the power of polishing with PoolSeq data

We constructed a chromosome-level assembly for Pieris macdunnoughii, a North American butterfly whose involvement in an evolutionary trap imposed by invasive Eurasian mustard has made it an emerging model system for studying maladaptation in plant-insect interactions. We employed an efficient, cost-effective approach using Oxford Nanopore long reads to achieve a high-quality genome assembly. We further improved the genome by polishing with pooled Illumina short-read data, demonstrating for the first time that high-coverage PoolSeq reads are equally effective at improving long-read genomes as reads from a single individual. Our final assembly comprised 106 contigs and a total of 316,549,294 bases, with an N50 of 5.2Mb. Short read sequences used for hybrid polishing are archived here.