Abstract：
Direct observation is central to our understanding of adaptation, but evolution is rarely documented in a large, multicellular organism for more than a few generations. In this study, we observed evolution across a century-scale competition experiment, barley composite cross II (CCII). CCII was founded in 1929 in Davis, California, with thousands of genotypes, but we found that natural selection has massively reduced genetic diversity, leading to a single lineage constituting most of the population by generation 50. Selection favored alleles originating from climates similar to that of Davis and targeted loci contributing to reproductive development, including the barley diversification loci Vrs1, HvCEN, Ppd-H1, and Vrn-H2. Our findings point to selection as the predominant force shaping genomic variation in one of the world\'s oldest biological experiments.
摘要：
直接观察是我们理解适应的核心，但是进化很少被记录在一个大的，几代以上的多细胞生物。在这项研究中,我们观察了一个世纪规模的竞争实验的演变，大麦复合杂交II(CCII)。CCII于1929年在戴维斯成立，加州,有成千上万的基因型，但是我们发现自然选择大大降低了遗传多样性，导致50代时构成大部分人口的单一血统。选择有利于源自与戴维斯相似的气候的等位基因和有助于生殖发育的目标基因座，包括大麦多样化基因座Vrs1、HvCEN、Ppd-H1和Vrn-H2。我们的发现指出，选择是世界上最古老的生物学实验之一中塑造基因组变异的主要力量。
