Repar Jelena, Warnecke Tobias
Molecular Systems Group, MRC London Institute of Medical Sciences (LMS), London, United Kingdom.
Institute of Clinical Sciences, Molecular Systems Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom.
Mol Biol Evol. 2017 Aug 1;34(8):1902-1911. doi: 10.1093/molbev/msx127.
Inversions are a major contributor to structural genome evolution in prokaryotes. Here, using a novel alignment-based method, we systematically compare 1,651 bacterial and 98 archaeal genomes to show that inversion landscapes are frequently biased toward (symmetric) inversions around the origin-terminus axis. However, symmetric inversion bias is not a universal feature of prokaryotic genome evolution but varies considerably across clades. At the extremes, inversion landscapes in Bacillus-Clostridium and Actinobacteria are dominated by symmetric inversions, while there is little or no systematic bias favoring symmetric rearrangements in archaea with a single origin of replication. Within clades, we find strong but clade-specific relationships between symmetric inversion bias and different features of adaptive genome architecture, including the distance of essential genes to the origin of replication and the preferential localization of genes on the leading strand. We suggest that heterogeneous selection pressures have converged to produce similar patterns of structural genome evolution across prokaryotes.
倒位是原核生物基因组结构进化的主要促成因素。在此，我们使用一种基于比对的新方法，系统地比较了1651个细菌基因组和98个古菌基因组，结果表明倒位图谱常常偏向于围绕着原点 - 终点轴的（对称）倒位。然而，对称倒位偏向并非原核生物基因组进化的普遍特征，而是在不同进化枝之间存在很大差异。在极端情况下，芽孢杆菌 - 梭菌属和放线菌中的倒位图谱以对称倒位为主，而在具有单个复制起点的古菌中，几乎没有或根本没有偏向对称重排的系统偏差。在进化枝内部，我们发现对称倒位偏向与适应性基因组结构的不同特征之间存在强烈但特定于进化枝的关系，这些特征包括必需基因到复制起点的距离以及基因在前导链上的优先定位。我们认为，异质选择压力已经趋同，从而在原核生物中产生了相似的基因组结构进化模式。
