细胞内竞争形成质粒种群动态，这一成果由
课题组研究人员测量了竞争大肠杆菌质粒的细胞内适应性，并表征了它们的漂移和选择动力学。课题组合成了质粒二聚体，它可以以一种可控的方式分裂，以创造平衡的竞争，课题组在实验中对此进行了探索。由于基于甲基化的复制控制，不相容的质粒共存的时间延长了。
此外，转录活性较低的质粒表现出细胞内优势并优先固定，有利于基因丢失。关键的是，固定依赖于质粒转录和翻译之间的相互作用。他们的研究结果表明，质粒进化是由细胞内和细胞间的动力学驱动的。
据悉，从多细胞生物的种群到自私的遗传因素，生物组织水平之间的冲突是进化的核心。质粒是染色体外自我复制的遗传元件，它们面临来自宿主的选择压力，但也在宿主细胞内竞争复制资源。虽然理论表明细胞内选择对质粒进化很重要，但对这些动力学的实验测量仍然很有限。
附：英文原文
Title: Intracellular competition shapes plasmid population dynamics
Author: Fernando Rossine, Carlos Sanchez, Daniel Eaton, Johan Paulsson, Michael Baym
Issue&Volume: 2025-11-20
Abstract: From populations of multicellular organisms to selfish genetic elements, conflicts between levels of biological organization are central to evolution. Plasmids are extrachromosomal, self-replicating genetic elements that face selective pressures from their hosts but also compete within the host cell for replication resources. While theory indicates that within-cell selection matters for plasmid evolution, experimental measurement of these dynamics has remained elusive. Here, we measure within-cell fitness of competing Escherichia coli plasmids and characterize their drift and selective dynamics. We made synthetic plasmid dimers that can be split in a controlled way to create balanced competition, which we probed experimentally. Incompatible plasmids coexist for an extended time due to methylation-based replication control. Moreover, less transcriptionally active plasmids display a within-cell advantage and fix preferentially, favoring gene loss. Critically, fixation depends non-trivially on the interplay between plasmid transcription and translation. Our results show that plasmid evolution is driven by within- and between-cell dynamics.
DOI: adx0665
Source: https://www.science.org/doi/10.1126/science.adx0665