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.

中文翻译：

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在一项长达一个世纪的大麦实验中，自然选择驱动了新兴的遗传同质性


直接观察是我们理解适应的核心，但大型多细胞生物体的进化很少有超过几代的记录。在这项研究中，我们观察了一个世纪规模的竞争实验大麦复合杂交 II (CCII) 的进化。 CCII 于 1929 年在加利福尼亚州戴维斯成立，拥有数千种基因型，但我们发现自然选择极大地减少了遗传多样性，导致第 50 代时大多数人口由单一谱系构成。选择青睐来自与该气候相似的气候的等位基因。戴维斯和有助于生殖发育的目标基因座，包括大麦多样化基因座电压1 ,氢氯乙烯, Pd-H1 ， 和Vrn-H2 。我们的研究结果表明，在世界上最古老的生物实验之一中，选择是塑造基因组变异的主导力量。