Kunisawa T
Department of Applied Biological Sciences, Science University of Tokyo, Noda, Japan.
J Mol Evol. 1995 Jun;40(6):585-93. doi: 10.1007/BF00160505.
DNA sequence segments conserved since divergence of Escherichia coli and Bacillus subtilis were identified, using the GenBank sequence database. Chromosomal locations of the conserved segments were compared between the two bacteria, and the following three features were observed. (1) Although the two genomes are nearly identical in size, chromosomal arrangements of the conserved segments are considerably different from each other. (2) In many cases, chromosomal locations of a conserved segment in the two species have deviated from each other by a multiple of 60 degrees. (3) There are many instances in which a contiguous segment in one genome is split into two or more segments located at distinct positions in the other genome, and these split segments were found to tend to lie on the E. coli or B. subtilis genome separated by distances of multiples of 60 degrees. On the basis of these observations, genome organizations of the two bacteria were discussed in terms of genome doublings as well as random chromosomal rearrangements.
利用GenBank序列数据库，鉴定出了自大肠杆菌和枯草芽孢杆菌分化以来保守的DNA序列片段。比较了这两个细菌中保守片段的染色体位置，观察到以下三个特征。（1）尽管两个基因组大小几乎相同，但保守片段的染色体排列彼此差异很大。（2）在许多情况下，两个物种中保守片段的染色体位置彼此偏离了60度的倍数。（3）存在许多情况，其中一个基因组中的连续片段在另一个基因组中被分成两个或更多个位于不同位置的片段，并且发现这些分裂片段倾向于位于大肠杆菌或枯草芽孢杆菌基因组上，彼此相隔60度的倍数距离。基于这些观察结果，从基因组加倍以及随机染色体重排的角度讨论了这两种细菌的基因组组织。
