Department of Grassland Resources and Ecology, College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
National Engineering Laboratory for Animal Breeding, Department of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Genome Res. 2024 Aug 20;34(7):997-1007. doi: 10.1101/gr.278794.123.
We present the first chromosome-level genome assembly of the grasshopper, , 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 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.
我们呈现了直翅目昆虫——最大的昆虫基因组之一——的首个染色体水平的基因组组装。我们利用雌性（XX）和雄性（X0）之间的覆盖度差异，来鉴定 X 染色体的基因组成，发现 X 染色体在体细胞组织中表现出完全的剂量补偿，而在睾丸表达的基因中表现出基因缺失。来自直翅目昆虫的 X 连锁基因内容在七个昆虫目，即直翅目、蜻蜓目、竹节虫目、半翅目、脉翅目、鞘翅目和双翅目中高度保守，尽管经历了 4 亿年的分化，800Mb 的蝗虫 X 染色体与果蝇祖先的 X 染色体同源，这表明性染色体具有高度相似的基因内容，可能是重复起源，或者 X 染色体长期以来保持保守。我们利用 X 染色体的广泛保守性来检测快速进化的动态，发现与 X 保守基因的缓慢进化相比，新的 X 连锁基因最近发生了爆发式进化。
