Maiden M C
Division of Bacteriology, National Institute for Biological Standards and Control, South Mimms, UK.
FEMS Microbiol Lett. 1993 Sep 15;112(3):243-50. doi: 10.1111/j.1574-6968.1993.tb06457.x.
Information of the biochemistry and genetics of bacterial species, usually obtained by the study of single isolates, is enhanced by studies of populations of bacteria. Recent advances in molecular technology, particularly polymerase chain reaction-based nucleotide sequence analysis, provide powerful tools for the study of population genetics. Data obtained by such techniques indicate that, while some bacterial species have a clonal population structure, others are non-clonal or panmictic. Clonal populations are a consequence of asexual reproduction by binary fission; panmictic population structures result from 'horizontal' exchange of genetic material between clones. A consequence of horizontal genetic exchange is mosaic gene structures, recognisable by comparisons of nucleotide sequences. In transformable bacteria, for example the human pathogen Neisseria meningitidis, several different genes, including the gene encoding the class 1 outer membrane protein, a major surface antigen, are mosaics. This genetic process has implications both for vaccine design and in the interpretation of epidemiological data.
通常通过对单个分离株的研究获得的细菌物种生物化学和遗传学信息，因对细菌群体的研究而得到加强。分子技术的最新进展，特别是基于聚合酶链反应的核苷酸序列分析，为群体遗传学研究提供了强大工具。通过这些技术获得的数据表明，虽然一些细菌物种具有克隆群体结构，但其他物种则是非克隆的或随机交配的。克隆群体是二分裂无性繁殖的结果；随机交配群体结构是克隆之间遗传物质“水平”交换的结果。水平基因交换的一个结果是镶嵌基因结构，可通过核苷酸序列比较识别。例如在可转化细菌中，人类病原体脑膜炎奈瑟菌的几个不同基因，包括编码1类外膜蛋白（一种主要表面抗原）的基因，都是镶嵌体。这种遗传过程对疫苗设计和流行病学数据的解释都有影响。
