Acar Murat, Mettetal Jerome T, van Oudenaarden Alexander
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nat Genet. 2008 Apr;40(4):471-5. doi: 10.1038/ng.110. Epub 2008 Mar 23.
A classic problem in population and evolutionary biology is to understand how a population optimizes its fitness in fluctuating environments. A population might enhance its fitness by allowing individual cells to stochastically transition among multiple phenotypes, thus ensuring that some cells are always prepared for an unforeseen environmental fluctuation. Here we experimentally explore how switching affects population growth by using the galactose utilization network of Saccharomyces cerevisiae. We engineered a strain that randomly transitions between two phenotypes as a result of stochastic gene expression. Each phenotype was designed to confer a growth advantage over the other phenotype in a certain environment. When we compared the growth of two populations with different switching rates, we found that fast-switching populations outgrow slow switchers when the environment fluctuates rapidly, whereas slow-switching phenotypes outgrow fast switchers when the environment changes rarely. These results suggest that cells may tune inter-phenotype switching rates to the frequency of environmental changes.
群体生物学和进化生物学中的一个经典问题是理解群体如何在波动的环境中优化其适应性。群体可能通过允许单个细胞在多种表型之间随机转换来提高其适应性，从而确保一些细胞始终为不可预见的环境波动做好准备。在这里，我们通过使用酿酒酵母的半乳糖利用网络，实验性地探索转换如何影响群体生长。我们构建了一个菌株，由于随机基因表达，该菌株在两种表型之间随机转换。每种表型在特定环境中都被设计为比另一种表型具有生长优势。当我们比较具有不同转换率的两个群体的生长情况时，我们发现当环境快速波动时，快速转换的群体比慢速转换的群体生长得快，而当环境很少变化时，慢速转换的表型比快速转换的表型生长得快。这些结果表明，细胞可能会根据环境变化的频率来调整表型间的转换率。
