Recombination within natural populations of pathogenic bacteria: Short-term empirical estimates and long-term phylogenetic consequences
Recombination within natural populations of pathogenic bacteria: Short-term empirical estimates and long-term phylogenetic consequences
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DOI：
10.1073/pnas.98.1.182
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发表时间：
2001-01-02
影响因子：
11.1
通讯作者：
Spratt, BG
中科院分区：
文献类型：
--
作者：
Feil, EJ;Holmes, EC;Spratt, BG
在细菌群体中鉴定出克隆体通常被视为重组率低的证据，但这种推断的有效性很少被检验。我们运用基因树之间一致性的统计检验来检测六种细菌病原体中重组的程度和重要性。对于脑膜炎奈瑟氏菌、肺炎链球菌、化脓性链球菌和金黄色葡萄球菌，使用七个持家基因重建的最大似然树之间的一致性在大多数情况下并不比每棵树与随机拓扑结构的树之间的一致性更好。在这四个物种（包括可自然转化和不可自然转化的物种）中基因树之间缺乏一致性，在三个案例中得到了克隆多样化过程中重组与点突变的高比率的支持（对于化脓性链球菌无法估计此参数）。相比之下，为流感嗜血杆菌和致病性大肠杆菌构建的基因树显示出更高程度的一致性，表明重组率较低。因此，重组的影响在细菌物种之间有所不同，但在许多物种中足以消除基因树中的系统发育信号。
The identification of clones within bacterial populations is often taken as evidence for a low rate of recombination, but the validity of this inference is rarely examined. We have used statistical tests of congruence between gene trees to examine the extent and significance of recombination in six bacterial pathogens. For Neisseria meningitidis, Streptococcus pneumoniae, Streptococcos pyogenes, and Staphylococcus aureus, the congruence between the maximum likelihood trees reconstructed using seven house-keeping genes was in most cases no better than that between each tree and trees of random topology. The lack of congruence between gene trees in these four species, which include both naturally transformable and nontransformable species, is in three cases supported by high ratios of recombination to point mutation during clonal diversification (estimates of this parameter were not possible for Strep. pyogenes). In contrast, gene trees constructed for Hemophilus influenzae and pathogenic isolates of Escherichia coli showed a higher degree of congruence, suggesting lower rates of recombination. The impact of recombination therefore varies between bacterial species but in many species is sufficient to obliterate the phylogenetic signal in gene trees.