Francino M P, Ochman H
Department of Biology, University of Rochester, NY 14627, USA.
Trends Genet. 1997 Jun;13(6):240-5. doi: 10.1016/S0168-9525(97)01118-9.
The complementary strands of DNA differ with respect to replication and transcription. Both of these processes are asymmetric and can bias the occurrence of mutations between the strands: during replication, the discontinuous lagging strand undergoes certain errors at higher rates, and transcription overexposes the nontranscribed strand to DNA damage while targeting repair enzymes to the transcribed strand. While biases introduced during replication apparently have little impact on sequence evolution, the effects of transcription are observed in the asymmetric patterns of substitution in bacterial genes and might be influencing genome-wide patterns of base composition.
DNA的互补链在复制和转录方面存在差异。这两个过程都是不对称的，并且会使链间突变的发生产生偏差：在复制过程中，不连续的滞后链发生某些错误的频率更高，而转录会使非转录链过度暴露于DNA损伤，同时将修复酶靶向转录链。虽然复制过程中引入的偏差显然对序列进化影响不大，但转录的影响在细菌基因的不对称替代模式中可以观察到，并且可能正在影响全基因组的碱基组成模式。
