Tillier E R, Collins R A
Department of Molecular and Medical Genetics, University of Toronto, 1 King's College Circle, Toronto, Canada, M5S 1A8.
J Mol Evol. 2000 Nov;51(5):459-63. doi: 10.1007/s002390010108.
In many bacterial genomes, the leading and lagging strands have different skews in base composition; for example, an excess of guanosine compared to cytosine on the leading strand. We find that Chlamydia genes that have switched their orientation relative to the direction of replication, for example by inversion, acquire the skew of their new "host" strand. In contrast to most evolutionary processes, which have unpredictable effects on the sequence of a gene, replication-related skews reflect a directional evolutionary force that causes predictable changes in the base composition of switched genes, resulting in increased DNA and amino acid sequence divergence.
在许多细菌基因组中，前导链和后随链在碱基组成上具有不同的偏向性；例如，前导链上鸟苷相对于胞嘧啶过量。我们发现，衣原体基因相对于复制方向改变了其方向，例如通过倒位，会获得其新“宿主”链的偏向性。与大多数对基因序列具有不可预测影响的进化过程不同，与复制相关的偏向性反映了一种定向进化力量，这种力量会导致转换基因的碱基组成发生可预测的变化，从而导致DNA和氨基酸序列分歧增加。
