Suerbaum S, Smith J M, Bapumia K, Morelli G, Smith N H, Kunstmann E, Dyrek I, Achtman M
Department of Medical Microbiology, Ruhr-Universität Bochum, D-44780 Bochum, Germany.
Proc Natl Acad Sci U S A. 1998 Oct 13;95(21):12619-24. doi: 10.1073/pnas.95.21.12619.
Sequences of three gene fragments (flaA, flaB, and vacA) from Helicobacter pylori strains isolated from patients in Germany, Canada, and South Africa were analyzed for diversity and for linkage equilibrium by using the Homoplasy Test and compatibility matrices. Horizontal genetic exchange in H. pylori is so frequent that different loci and polymorphisms within each locus are all at linkage equilibrium. These results indicate that H. pylori is panmictic. Comparisons with sequences from Escherichia coli, Neisseria meningitidis, and Drosophila melanogaster showed that recombination in H. pylori was much more frequent than in other species. In contrast, when multiple family members infected with H. pylori were investigated, some strains were indistinguishable at all three loci. Thus, H. pylori is clonal over short time periods after natural transmission.
对从德国、加拿大和南非患者中分离出的幽门螺杆菌菌株的三个基因片段(flaA、flaB和vacA)序列进行了分析,以通过使用同塑性检验和兼容性矩阵来研究其多样性和连锁平衡。幽门螺杆菌中的水平基因交换非常频繁,以至于每个基因座内的不同基因座和多态性都处于连锁平衡状态。这些结果表明幽门螺杆菌是随机交配的。与大肠杆菌、脑膜炎奈瑟菌和黑腹果蝇的序列比较表明,幽门螺杆菌中的重组比其他物种更为频繁。相比之下,当对多个感染幽门螺杆菌的家庭成员进行调查时,一些菌株在所有三个基因座上都无法区分。因此,幽门螺杆菌在自然传播后的短时间内是克隆性的。