Self-replication and evolution under selective pressure are inherent phenomena in life, and but few artificial systems exhibit these phenomena^{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17}. We have designed a system of DNA origami rafts that exponentially replicates a seed pattern, doubling the copies in each diurnal-like cycle of temperature and ultraviolet illumination, producing more than 7 million copies in 24 cycles. We demonstrate environmental selection in growing populations by incorporating pH-sensitive binding in two subpopulations. In one species, pH-sensitive triplex DNA bonds enable parent–daughter templating, while in the second species, triplex binding inhibits the formation of duplex DNA templating. At pH 5.3, the replication rate of species I is ∼1.3–1.4 times faster than that of species II. At pH 7.8, the replication rates are reversed. When mixed together in the same vial, the progeny of species I replicate preferentially at pH 7.8; similarly at pH 5.3, the progeny of species II take over the system. This addressable selectivity should be adaptable to the selection and evolution of multi-component self-replicating materials in the nanoscopic-to-microscopic size range.

在选择性压力下的自我复制和进化是生活中固有的现象，但是很少有人工系统表现出这些现象^{1,2,3,4,5,6,7,8,9,10,11,12,13,14， 15,16,17}。我们设计了一个DNA折纸筏系统，该系统以指数方式复制了种子图案，在每个类似温度和紫外线的昼夜循环中，拷贝数都翻了一番，在24个循环中产生了超过700万个拷贝。我们通过在两个亚群中整合pH敏感结合来证明正在增长的人口中的环境选择。在一个物种中，pH敏感的三链DNA键可实现亲子模板化，而在第二个物种中，三链结合可抑制双链DNA模板的形成。在pH 5.3，物种I的复制速率为〜比II类快1.3–1.4倍。在pH 7.8下，复制速率相反。当在同一小瓶中混合在一起时，物种I的后代会优先在pH 7.8下复制；同样在pH 5.3时，物种II的后代接管了该系统。这种可寻址的选择性应适应纳米级至微米级尺寸范围内多组分自复制材料的选择和发展。