Adaptation to structurally different environments
Adaptation to structurally different environments
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DOI：
10.1098/rspb.1996.0243
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发表时间：
1996-12-22
影响因子：
4.7
通讯作者：
Korona, R
中科院分区：
文献类型：
--
作者：
Korona, R
环境的物理结构可能对细菌特别重要，细菌可以作为自由漂浮的细胞生活或在固体表面形成密集的聚集体。本研究探讨了居住在结构不同的环境中是否会促进不同适应的进化。共安排了两个实验栖息地：在均匀的细胞自由浮动和混合;在结构化的一个，他们生长不受干扰，形成层上的固体培养基。这些种群经过1000代繁殖。然后将进化后的克隆体与它们的共同祖先克隆体的适合度进行比较。衍生克隆最适合在环境中，他们已经进化，但他们的健身也在结构上的陌生环境中得到增强。这可能意味着细菌不仅适应栖息地结构，而且适应营养条件，这在两种选择环境中是相同的。出于这个原因，在不同的生长培养基中重复适合度测量。现在，已经适应了同质栖息地的细菌在非同质栖息地表现出明显的适应性损失，反之亦然，这表明进化专业化可能导致适应性权衡。这样，环境通才的产生可能会受到阻碍。另一个广泛的发现是，在结构化的栖息地进化的克隆之间的适应性差异更高，这意味着在非同质环境中的进化产生了更大的适应多样性。
The physical structure of the environment may be especially important to bacteria, which can live as free-floating cells or form dense aggregations on solid surfaces. The present study asks whether inhabiting structurally different environments promotes the evolution of distinct adaptations. A total of two experimental habitats were arranged: in the homogeneous one the cells were free-floating and mixed; in the structured one they grew undisturbed, forming layers on a solid medium. The populations were propagated through 1000 generations. Then the fitness of the evolved clones was compared with that of their common progenitor clone. The derived clones were most fit in the environment in which they had evolved, but their fitness was enhanced also in the structurally unfamiliar environment. This could mean that the bacteria adapted not only to the habitat structure but also to nutritional conditions, which were the same in both selection environments. For this reason, the fitness measurements were repeated in a different growth medium. Now the bacteria that had adapted to the homogeneous habitat demonstrated a significant loss of fitness in the non-homogeneous one, and vice versa, suggesting that evolutionary specialization may result in fitness trade-offs. In this way the origination of environmental generalists might be impeded. Another broad finding was that variation in fitness was higher among clones evolved in the structured habitat, implying that evolution in a non-homogeneous environment produces a greater diversity of adaptations.