Chromosome-scale genome assemblies of aphids reveal extensively rearranged autosomes and long-term conservation of the X chromosome
Chromosome-scale genome assemblies of aphids reveal extensively rearranged autosomes and long-term conservation of the X chromosome
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蚜虫的染色体规模基因组组装揭示了常染色体的广泛重排和 X 染色体的长期保守
DOI：
10.1101/2020.03.24.006411
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Mathers T
中科院分区：
文献类型：
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作者：
Mathers T
染色体重排可以说是最引人注目的突变类型，通常导致快速进化和物种形成。然而，染色体动力学仅在少数模型系统中在序列水平上进行了研究。在昆虫中，双翅目和鳞翅目在整个染色体或染色体臂的尺度上具有保守的基因组结构。这是否反映了昆虫基因组进化的多样性是值得怀疑的，因为许多物种表现出快速的核型进化。本研究利用新生成的桃蚜（Myzus persicae）和豌豆蚜（Acyrthosiphon pisum）的染色体尺度基因组组合，以及先前发表的玉米叶蚜（Rhopalosiphum maidis）的染色体尺度基因组组合，研究了蚜虫（半纲植物害虫的重要类群）的染色体进化。我们发现，在过去的30年中，蚜虫常染色体发生了戏剧性的重组，以至于无法确定大蚜虫（Myzus persicaeandAcyrthosiphon pisum）和蚜虫（Rhopalosiphum maidis）的染色体同源性。相比之下，蚜虫性(X)染色体的基因含量在序列快速进化、基因低表达和高转座元件负荷的情况下保持不变。为了测试基因组结构的快速进化是否是半翅目昆虫的标志，我们将我们的蚜虫组合与两种吸血半翅目昆虫（Rhodnius prolixusandTriatoma rubrofasciata）的染色体规模组合进行了比较。尽管分化程度更高，但吸血半纲动物仍保持着同质性。蚜虫常染色体的特殊结构进化速率使它们成为研究大规模基因组重排在进化中的作用的重要新兴模型系统。
Chromosome rearrangements are arguably the most dramatic type of mutations, often leading to rapid evolution and speciation. However, chromosome dynamics have only been studied at the sequence level in a small number of model systems. In insects, Diptera and Lepidoptera have conserved genome structure at the scale of whole chromosomes or chromosome arms. Whether this reflects the diversity of insect genome evolution is questionable given that many species exhibit rapid karyotype evolution. Here, we investigate chromosome evolution in aphids—an important group of hemipteran plant pests—using newly generated chromosome-scale genome assemblies of the green peach aphid (Myzus persicae) and the pea aphid (Acyrthosiphon pisum), and a previously published assembly of the corn-leaf aphid (Rhopalosiphum maidis). We find that aphid autosomes have undergone dramatic reorganization over the last 30 My, to the extent that chromosome homology cannot be determined between aphids from the tribes Macrosiphini (Myzus persicaeandAcyrthosiphon pisum) and Aphidini (Rhopalosiphum maidis). In contrast, gene content of the aphid sex (X) chromosome remained unchanged despite rapid sequence evolution, low gene expression, and high transposable element load. To test whether rapid evolution of genome structure is a hallmark of Hemiptera, we compared our aphid assemblies with chromosome-scale assemblies of two blood-feeding Hemiptera (Rhodnius prolixusandTriatoma rubrofasciata). Despite being more diverged, the blood-feeding hemipterans have conserved synteny. The exceptional rate of structural evolution of aphid autosomes renders them an important emerging model system for studying the role of large-scale genome rearrangements in evolution.