Wirth Thierry, Hildebrand Falk, Allix-Béguec Caroline, Wölbeling Florian, Kubica Tanja, Kremer Kristin, van Soolingen Dick, Rüsch-Gerdes Sabine, Locht Camille, Brisse Sylvain, Meyer Axel, Supply Philip, Niemann Stefan
Department of Biology, Lehrstuhl für Zoologie und Evolutionsbiologie, University of Konstanz, Konstanz, Germany.
PLoS Pathog. 2008 Sep 19;4(9):e1000160. doi: 10.1371/journal.ppat.1000160.
The evolutionary timing and spread of the Mycobacterium tuberculosis complex (MTBC), one of the most successful groups of bacterial pathogens, remains largely unknown. Here, using mycobacterial tandem repeat sequences as genetic markers, we show that the MTBC consists of two independent clades, one composed exclusively of M. tuberculosis lineages from humans and the other composed of both animal and human isolates. The latter also likely derived from a human pathogenic lineage, supporting the hypothesis of an original human host. Using Bayesian statistics and experimental data on the variability of the mycobacterial markers in infected patients, we estimated the age of the MTBC at 40,000 years, coinciding with the expansion of "modern" human populations out of Africa. Furthermore, coalescence analysis revealed a strong and recent demographic expansion in almost all M. tuberculosis lineages, which coincides with the human population explosion over the last two centuries. These findings thus unveil the dynamic dimension of the association between human host and pathogen populations.
结核分枝杆菌复合群（MTBC）是最成功的细菌病原体群体之一，其进化时间和传播情况在很大程度上仍不为人知。在此，我们以分枝杆菌串联重复序列作为遗传标记，表明MTBC由两个独立的进化枝组成，一个仅由来自人类的结核分枝杆菌谱系构成，另一个则由动物和人类分离株组成。后者可能也源自人类致病谱系，这支持了最初人类宿主的假说。利用贝叶斯统计以及感染患者中分枝杆菌标记变异的实验数据，我们估计MTBC的年代为4万年前，这与“现代”人类从非洲向外扩张的时间相符。此外，溯祖分析显示几乎所有结核分枝杆菌谱系近期都出现了强烈的种群扩张，这与过去两个世纪的人口爆炸相吻合。因此，这些发现揭示了人类宿主与病原体群体之间关联的动态维度。
