Host diversity limits the evolution of parasite local adaptation
Host diversity limits the evolution of parasite local adaptation
复制标题
宿主多样性限制了寄生虫局部适应的进化
DOI：
10.1111/mec.13917
复制
发表时间：
2016
影响因子：
4.9
通讯作者：
Morley D
中科院分区：
文献类型：
--
作者：
Morley D
宿主和寄生虫之间相互作用的特异性可以导致局部适应。然而，局部适应的程度预计取决于寄主种群内抗性等位基因的多样性；增加寄主多样性应该会降低寄生虫的平均感染力，从而降低局部适应。在这项研究中，我们使用具有集群规则间隔短回文重复/CRISPR相关(CRISPR/Cas)免疫的细菌与其噬菌体之间的高度特异性相互作用来经验性地检验这一预测。细菌通过将噬菌体衍生的间隔区序列整合到宿主基因组上的CRISPR位点来获得对噬菌体的免疫力，而噬菌体可以通过突变目标序列来逃避特定克隆的CRISPR介导的免疫。我们发现，在暴露于噬菌体的宿主种群中自然进化的高水平的CRISPR等位基因多样性(因为每个细菌克隆都捕获了一个唯一的噬菌体衍生序列)阻止了噬菌体变得局部适应。通过控制宿主群体中CRISPR等位基因的数量，我们表明，只有当CRISPR等位基因多样性较低时，噬菌体才能局部适应细菌宿主。
Specificity in the interactions between hosts and their parasites can lead to local adaptation. However, the degree of local adaptation is predicted to depend upon the diversity of resistance alleles within the host population; increasing host diversity should decrease mean parasite infectivity and hence reduce local adaptation. In this study, we empirically test this prediction using the highly specific interactions between bacteria with clustered regularly interspaced short palindromic repeats/CRISPR‐associated (CRISPR/Cas) immunity and their bacteriophage. Bacteria acquire immunity to phage by incorporating a phage‐derived spacer sequence into CRISPR loci on the host genome, and phage can escape the CRISPR‐mediated immunity of a specific clone by mutating the targeted sequence. We found that high levels of CRISPR allele diversity that naturally evolve in host populations exposed to phage (because each bacterial clone captures a unique phage‐derived sequence) prevents phage from becoming locally adapted. By manipulating the number of CRISPR alleles in the host population, we show that phage can become locally adapted to their bacterial hosts but only when CRISPR allele diversity is low.
影响因子：
3.2
作者：
Deveau, Helene;Barrangou, Rodolphe;Moineau, Sylvain
通讯作者：
Moineau, Sylvain