DYNAMICS OF ADAPTATION AND DIVERSIFICATION - A 10,000-GENERATION EXPERIMENT WITH BACTERIAL-POPULATIONS
DYNAMICS OF ADAPTATION AND DIVERSIFICATION - A 10,000-GENERATION EXPERIMENT WITH BACTERIAL-POPULATIONS
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DOI：
10.1073/pnas.91.15.6808
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发表时间：
1994-07-19
影响因子：
11.1
通讯作者：
TRAVISANO, M
中科院分区：
文献类型：
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作者：
LENSKI, RE;TRAVISANO, M
我们跟踪了在相同环境中繁殖了10，000代的12个大肠杆菌种群的进化变化。形态（细胞大小）和健身（测量与祖先的竞争）迅速进化的第一个2000代左右后，人口被引入到实验环境，但在过去的5000代几乎是静态的。虽然在相同的环境中进化，复制种群的形态和平均健身显着偏离彼此。在平均适应度的分歧是持续的，这意味着人口已接近不同的适应度高峰不等的高度在适应性景观。虽然实验的时间尺度和环境是微进化的范围内，我们的实验旨在解决有关起源的问题，以及遗传和表型新奇的命运，适应的可重复性，谱系的多样化，从而进化历史的独特性的原因和后果。事实上，我们观察到宏观进化动力学的几个标志，包括快速进化和停滞期，改变性状之间的功能关系，以及起源和分支趋势的一致性。我们的研究结果支持赖特的解释，其中机会事件（突变和漂移）在适应性进化中起着重要作用，作为生物体结构的基础的复杂的遗传相互作用也是如此。
We followed evolutionary change in 12 populations of Escherichia coli propagated for 10,000 generations in identical environments. Both morphology (cell size) and fitness (measured in competition with the ancestor) evolved rapidly for the first 2000 generations or so after the populations were introduced into the experimental environment, but both were nearly static for the last 5000 generations. Although evolving in identical environments, the replicate populations diverged significantly from one another in both morphology and mean fitness. The divergence in mean fitness was sustained and implies that the populations have approached different fitness peaks of unequal height in the adaptive landscape. Although the experimental time scale and environment were microevolutionary in scope, our experiments were designed to address questions concerning the origin as well as the fate of genetic and phenotypic novelties, the repeatability of adaptation, the diversification of lineages, and thus the causes and consequences of the uniqueness of evolutionary history. In fact, we observed several hallmarks of macroevolutionary dynamics, including periods of rapid evolution and stasis, altered functional relationships between traits, and concordance of anagenetic and cladogenetic trends. Our results support a Wrightian interpretation, in which chance events (mutation and drift) play an important role in adaptive evolution, as do the complex genetic interactions that underlie the structure of organisms.