Evidence for symmetric chromosomal inversions around the replication origin in bacteria.
Evidence for symmetric chromosomal inversions around the replication origin in bacteria.
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DOI：
10.1186/gb-2000-1-6-research0011
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发表时间：
2000
期刊：
影响因子：
12.3
通讯作者：
Salzberg SL
中科院分区：
文献类型：
--
作者：
Eisen JA;Heidelberg JF;White O;Salzberg SL
全基因组比较可以为生物学的许多方面提供很好的见解。然而，直到最近，比较主要是可能的只有远亲物种之间。完整的基因组序列现在可以从多组密切相关的菌株或物种中获得。通过比较最近完成的霍乱弧菌基因组序列， 肺炎链球菌和结核分枝杆菌的密切相关的物种-大肠杆菌，化脓性链球菌和麻风分枝杆菌，分别-我们已经确定了一个不寻常的和以前未观察到的细菌基因组结构的功能。每对物种之间的保守序列（包括DNA和蛋白质）的散点图产生了一个独特的X形模式，我们称之为X对齐。这些比对的关键特征是它们在复制起点和末端周围具有对称性;也就是说，特定保守特征（DNA或蛋白质）与复制起点（或末端）的距离在密切相关的物种对之间是保守的。在一些基因组中也发现了统计学上显著的X-比对，这表明旁系同源特征的复制起点也是对称的。最可能的X-比对产生的机制涉及大的染色体倒位，其对称地逆转基因组序列在复制起点周围。在许多物种对之间的X-比对的发现表明，围绕起源的染色体倒位是细菌基因组进化的共同特征。
Whole-genome comparisons can provide great insight into many aspects of biology. Until recently, however, comparisons were mainly possible only between distantly related species. Complete genome sequences are now becoming available from multiple sets of closely related strains or species. By comparing the recently completed genome sequences of Vibrio cholerae, Streptococcus pneumoniae and Mycobacterium tuberculosis to those of closely related species - Escherichia coli, Streptococcus pyogenes and Mycobacterium leprae, respectively - we have identified an unusual and previously unobserved feature of bacterial genome structure. Scatterplots of the conserved sequences (both DNA and protein) between each pair of species produce a distinct X-shaped pattern, which we call an X-alignment. The key feature of these alignments is that they have symmetry around the replication origin and terminus; that is, the distance of a particular conserved feature (DNA or protein) from the replication origin (or terminus) is conserved between closely related pairs of species. Statistically significant X-alignments are also found within some genomes, indicating that there is symmetry about the replication origin for paralogous features as well. The most likely mechanism of generation of X-alignments involves large chromosomal inversions that reverse the genomic sequence symmetrically around the origin of replication. The finding of these X-alignments between many pairs of species suggests that chromosomal inversions around the origin are a common feature of bacterial genome evolution.