biostudies-literatureLi XBeijing Agriculture Innovation ConsortiumNational Key Research and Development Program of China997-1007https://www.ebi.ac.uk/biostudies/studies/S-EPMC11368200biostudies-literatureUnknown34(7)We present the first chromosome-level genome assembly of the grasshopper, <i>Locusta migratoria</i>, one of the largest insect genomes. We use coverage differences between females (XX) and males (X0) to identify the X Chromosome gene content, and find that the X Chromosome shows both complete dosage compensation in somatic tissues and an underrepresentation of testis-expressed genes. X-linked gene content from <i>L. migratoria</i> is highly conserved across seven insect orders, namely Orthoptera, Odonata, Phasmatodea, Hemiptera, Neuroptera, Coleoptera, and Diptera, and the 800 Mb grasshopper X Chromosome is homologous to the fly ancestral X Chromosome despite 400 million years of divergence, suggesting either repeated origin of sex chromosomes with highly similar gene content, or long-term conservation of the X Chromosome. We use this broad conservation of the X Chromosome to test for temporal dynamics to Fast-X evolution, and find evidence of a recent burst evolution for new X-linked genes in contrast to slow evolution of X-conserved genes.Genome researchThe grasshopper genome reveals long-term gene content conservation of the X Chromosome and temporal variation in X Chromosome evolution.PMC11368200BAIC02-2022Li XBan LMank JEfalseThe grasshopper genome reveals long-term gene content conservation of the X Chromosome and temporal variation in X Chromosome evolution.We present the first chromosome-level genome assembly of the grasshopper, <i>Locusta migratoria</i>, one of the largest insect genomes. We use coverage differences between females (XX) and males (X0) to identify the X Chromosome gene content, and find that the X Chromosome shows both complete dosage compensation in somatic tissues and an underrepresentation of testis-expressed genes. X-linked gene content from <i>L. migratoria</i> is highly conserved across seven insect orders, namely Orthoptera, Odonata, Phasmatodea, Hemiptera, Neuroptera, Coleoptera, and Diptera, and the 800 Mb grasshopper X Chromosome is homologous to the fly ancestral X Chromosome despite 400 million years of divergence, suggesting either repeated origin of sex chromosomes with highly similar gene content, or long-term conservation of the X Chromosome. We use this broad conservation of the X Chromosome to test for temporal dynamics to Fast-X evolution, and find evidence of a recent burst evolution for new X-linked genes in contrast to slow evolution of X-conserved genes.2024-01-01T00:00:00Z2024 Aug2026-06-02T06:48:56.938Z2026-04-15T03:15:31.979ZS-EPMC113682003910322810.1101/gr.278794.123