研究发现遗传背景影响变异
作者：小柯机器人 发布时间：2019/10/25 15:21:28
美国哈佛大学Michael M. Desai和加州大学旧金山分校Sergey Kryazhimskiy等研究人员的最新发现表明，适应性更高的酵母基因型对有害突变的抵抗力更弱。10月25日出版的《科学》杂志发表了这一成果。
为了了解稳健性如何随基因型的变化而变化，研究人员测量了一组酵母菌株中数百个单个插入突变的适应性效应。研究人员发现，适应性更好的菌株不那么稳健：它们具有适应性效应的分布，其均值较低且方差较高。之所以出现这些差异，是因为许多突变在生长较快的菌株中具有更强的有害作用。适应性和稳健性之间的这种负相关性意味着，针对稳健性的二阶选择将倾向于与针对适应性的一阶选择相冲突。
据了解，自然选择使种群趋向于更高的适应性，但是适应性和突变稳健性的二阶选择也会影响进化。在许多微生物系统中，递减回归的基因上位性导致趋向于适应性更强的基因型适应性降低的趋势，但是尚无类似的稳定性模式。
附：英文原文
Title:Higher-fitness yeast genotypes are less robust to deleterious mutations
Author:Milo S. Johnson1,2,3, Alena Martsul4, Sergey Kryazhimskiy4,*, Michael M. Desai1,2,3,5,*
Issue&Volume:2019/10/25
Abstract: Natural selection drives populations toward higher fitness, but second-order selection for adaptability and mutational robustness can also influence evolution. In many microbial systems, diminishing-returns epistasis contributes to a tendency for more-fit genotypes to be less adaptable, but no analogous patterns for robustness are known. To understand how robustness varies across genotypes, we measure the fitness effects of hundreds of individual insertion mutations in a panel of yeast strains. We find that more-fit strains are less robust: They have distributions of fitness effects with lower mean and higher variance. These differences arise because many mutations have more strongly deleterious effects in faster-growing strains. This negative correlation between fitness and robustness implies that second-order selection for robustness will tend to conflict with first-order selection for fitness.
DOI:10.1126/science.aay4199
期刊信息
Science：《科学》，创刊于1880年。隶属于美国科学促进会，最新IF：41.037