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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DOI：
10.1093/molbev/msaa246
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发表时间：
2021-03-09
影响因子：
10.7
通讯作者：
Hogenhout SA
中科院分区：
文献类型：
--
作者：
Mathers TC;Wouters RHM;Mugford ST;Swarbreck D;van Oosterhout C;Hogenhout SA
染色体重排可以说是最引人注目的突变类型，通常会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。在这里，我们调查染色体进化蚜虫的半翅目植物害虫的一个重要群体，使用新产生的染色体规模的基因组组装的绿色桃蚜（桃蚜）和豌豆蚜（豌豆蚜），和先前发表的大会玉米叶蚜（Rhopalosiphum major）。我们发现，在过去的30年里，蚜虫常染色体发生了剧烈的重组，以至于无法确定大管蚜族（桃蚜和豌豆蚜）和蚜虫族（玉米蚜）之间的染色体同源性。与此相反，蚜虫性别（X）染色体的基因内容保持不变，尽管快速序列进化，低基因表达，高转座因子负荷。为了测试基因组结构的快速进化是否是半翅目的标志，我们比较了我们的蚜虫组件与两个吸血半翅目（Rhodnius prolixus和Triatoma rubrofasciata）的染色体规模组件。尽管有更多的分歧，吸血的半翅目有保守的同线。蚜虫常染色体结构进化的特殊速率使其成为研究大规模基因组重排在进化中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 persicae and Acyrthosiphon 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 prolixus and Triatoma 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.