Deciphering the genomic characters of Ptygonotus chinghaiensis, a high-altitude grasshopper endemic to the Qinghai-Tibet Plateau, using low-coverage short-read sequencing.

Background: The Qinghai-Tibet Plateau, the world's youngest plateau, harbors a unique biodiversity shaped by its extreme environmental conditions. Genomic adaptations in its endemic insects, particularly those with large genomes such as grasshoppers (5.6-20 Gb), remain underexplored. Here, we present the first genomic analysis of Ptygonotus chinghaiensis, a high-altitude grasshopper endemic to this region, using low-coverage short-read sequencing.

Results: We estimated the haploid genome size of P. chinghaiensis at 12.17 Gb, with repetitive elements comprising 72.34%, predominantly DNA transposons, long terminal repeat (LTR) retrotransposons, and long interspersed nuclear elements (LINEs). Recent bursts of transposable elements (TEs) activity appear to have driven genomic expansion in this species. The 45S rRNA DNA operon, encoding the small subunit rRNA (ssrRNA), 5.8S rRNA, and large subunit rRNA (lsrRNA), was assembled into an 8,000 bp contig. The mitochondrial genome, spanning 16,750 bp, provided evolutionary insights, with divergence dated to 10.84 Mya during the late Neogene.

Conclusion: This study offers the first genome-wide characterization of a Qinghai-Tibet Plateau-endemic grasshopper, providing critical resources for understanding high-altitude adaptation and genomic evolution. These findings enhance our knowledge of adaptive mechanisms in extreme environments and the evolutionary dynamics of plateau-endemic insects.