近日，瑞士苏黎世大学Andreas Wagner课题组探明了隐形遗传变异通过开放不同的适应峰路径来加速进化。相关论文于2019年7月26日发表在《科学》杂志上。

为了阐明潜在的遗传机制，研究组在大肠杆菌中进行定向进化，从而在黄色荧光蛋白种群中积累变异体，将这些蛋白质向绿色荧光这一新表型进化。聚焦于相似的基因型上，相较于不具隐形变异的种群，具有隐形变异的种群进化的适应性基因型具有更好的多样性和适应性。隐形变异种群积累了中性或有害突变，打破了适应性突变产生秩序上的约束。如此，隐形变异打开了通向适应性基因型的路径，创造了历史偶然性。隐形变异通过允许不同的再生群体攀爬不同的适应峰，并探索其它不可接近的自适应区域来降低进化的可预测性。

据介绍，在不断进化的族群中，隐形遗传变异可以增强其适应性。
 

附：英文原文

Title: Cryptic genetic variation accelerates evolution by opening access to diverse adaptive peaks

Author: Jia Zheng, Joshua L. Payne, Andreas Wagner

Issue&Volume:Vol 365 Issue 6451

Abstract: Cryptic genetic variation can facilitate adaptation in evolving populations. To elucidate the underlying genetic mechanisms, we used directed evolution in Escherichia coli to accumulate variation in populations of yellow fluorescent proteins and then evolved these proteins toward the new phenotype of green fluorescence. Populations with cryptic variation evolved adaptive genotypes with greater diversity and higher fitness than populations without cryptic variation, which converged on similar genotypes. Populations with cryptic variation accumulated neutral or deleterious mutations that break the constraints on the order in which adaptive mutations arise. In doing so, cryptic variation opens paths to adaptive genotypes, creates historical contingency, and reduces the predictability of evolution by allowing different replicate populations to climb different adaptive peaks and explore otherwise-inaccessible regions of an adaptive landscape.

DOI: 10.1126/science.aax1837

Source:https://science.sciencemag.org/content/365/6451/347