The genetic structure of Borrelia afzelii varies with geographic but not ecological sampling scale
The genetic structure of Borrelia afzelii varies with geographic but not ecological sampling scale
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DOI：
10.1111/j.1420-9101.2010.02148.x
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发表时间：
2011-01-01
影响因子：
2.1
通讯作者：
Raberg, L.
中科院分区：
文献类型：
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作者：
Hellgren, O.;Andersson, M.;Raberg, L.
病原体的遗传结构是其潜在适应率的重要决定因素，因此可以影响宿主-寄生虫相互作用的动态。研究了阿氏疏螺旋体遗传结构随地理和生态采样尺度的变化。遗传结构以三个位点间的连锁不平衡度（LD）来衡量。为了验证地理和生态尺度的影响，我们计算了距离4-82 km的种群间或种群内以及不同哺乳动物宿主物种间或种群内的LD。种群间和寄主种间存在极显著的遗传变异。然而，也有全基因组重组的证据，LD主要是由于某些单倍型的流行传播，而不是缺乏重组。有趣的是，每个种群的LD程度都高于整个样本，即LD随地理尺度的减小而增加。相反，生态采样尺度对LD没有影响，强LD可能阻碍了适应进化的速度。我们的研究结果表明，这种影响在小的地理范围内可能特别强烈。
The genetic structure of a pathogen is an important determinant of its potential rate of adaptation and can thereby influence the dynamics of host-parasite interactions. We investigated how the genetic structure of Borrelia afzelii varies with geographic and ecological sampling scale. Genetic structure was measured as the degree of linkage disequilibrium (LD) across three loci. To test for the effects of geographic and ecological scale, we calculated LD across or within populations 4-82 km apart and across or within different mammal host species. There was highly significant LD across populations and host species. However, there was also evidence for genome-wide recombination, and the LD largely resulted from epidemic spread of certain haplotypes, rather than lack of recombination. Interestingly, the degree of LD was higher in each population than in the sample as a whole, i.e. LD increased with decreasing geographic scale. In contrast, there was no effect of ecological sampling scale on LD. Strong LD may impede the rate of adaptive evolution. Our results suggest this effect might be particularly strong at a small geographic scale.