Chromosome-level assembly of the club-legged grasshopper (Gomphocerus sibiricus) genome

Grasshoppers represent true outliers in genome sizes, both within insects and within animals in general. Their genomes are large and generally variable in sizes and feature a high abundance of repetitive DNA sequences. This has hampered the assembly of grasshopper genomes to the chromosome level. Here we present a chromosome-level reference genome for the club-legged grasshopper (Gomphocerus sibiricus, Acrididae: Gomphocerinae) using PacBio HiFi long-read and Hi-C sequencing technologies. In male haploid cells, the species has a chromosome set of n = 9 with an X0 sex-determination system, characterized by an absence of a Y chromosome. Our assembly spans 9.57 Gb in total, with 8.87 Gb organized into 9 chromosomes-8 autosomes and the X chromosome. The final assembly has a scaffold N50 value of 1.58 Gb, covers 96.7% single copy Insecta orthologs, and contains 42,665 predicted protein-coding genes and 43,385 mRNA transcripts. We compiled a curated, nonredundant, species-specific repeat library and used it to annotate repetitive DNA, covering 81.69% of the genome, mostly DNA transposons, long-interspersed nuclear element and long-terminal repeat retrotransposons. The genome of the club-legged grasshopper shows high degree of synteny with the locusts Schistocerca gregaria and Locusta migratoria, and the analysis strongly indicates 3 autosome-autosome centric fusions in Gomphocerinae. The genome offers a valuable resource for grasshopper genomics and for exploring the genetic basis of a transspecies color polymorphism.