The Roslin Institute, University of Edinburgh, Easter Bush Campus, Edinburgh EH25 9RG, UK.
Centro de Investigación y Tecnología Animal, Instituto Valenciano de Investigaciones Agrarias, Segorbe 12400, Spain.
Sci Adv. 2019 Nov 27;5(11):eaax0063. doi: 10.1126/sciadv.aax0063. eCollection 2019 Nov.
While many bacterial pathogens are restricted to single host species, some have the capacity to undergo host switches, leading to the emergence of new clones that are a threat to human and animal health. However, the bacterial traits that underpin a multihost ecology are not well understood. Following transmission to a new host, bacterial populations are influenced by powerful forces such as genetic drift that reduce the fixation rate of beneficial mutations, limiting the capacity for host adaptation. Here, we implement a novel experimental model of bacterial host switching to investigate the ability of the multihost pathogen to adapt to new species under continuous population bottlenecks. We demonstrate that beneficial mutations accumulated during infection can overcome genetic drift and sweep through the population, leading to host adaptation. Our findings highlight the remarkable capacity of some bacteria to adapt to distinct host niches in the face of powerful antagonistic population forces.
虽然许多细菌病原体仅限于单一宿主物种，但有些病原体有能力进行宿主转换，导致新克隆的出现，从而对人类和动物健康构成威胁。然而，支持多宿主生态系统的细菌特征还没有得到很好的理解。在传播到新宿主后，细菌种群会受到遗传漂变等强大力量的影响，从而降低有益突变的固定率，限制宿主适应的能力。在这里，我们实施了一种新的细菌宿主转换实验模型，以研究多宿主病原体在持续的种群瓶颈下适应新物种的能力。我们证明，感染过程中积累的有益突变可以克服遗传漂变并在种群中迅速传播，从而导致宿主适应。我们的研究结果强调了一些细菌在面对强大的拮抗种群力量时适应不同宿主小生境的惊人能力。
