Sánchez-Romero María A, Casadesús Josep
Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain.
Front Microbiol. 2021 Jun 4;12:685080. doi: 10.3389/fmicb.2021.685080. eCollection 2021.
Conrad Waddington's epigenetic landscape, a visual metaphor for the development of multicellular organisms, is appropriate to depict the formation of phenotypic variants of bacterial cells. Examples of bacterial differentiation that result in morphological change have been known for decades. In addition, bacterial populations contain phenotypic cell variants that lack morphological change, and the advent of fluorescent protein technology and single-cell analysis has unveiled scores of examples. Cell-specific gene expression patterns can have a random origin or arise as a programmed event. When phenotypic cell-to-cell differences are heritable, bacterial lineages are formed. The mechanisms that transmit epigenetic states to daughter cells can have strikingly different levels of complexity, from the propagation of simple feedback loops to the formation of complex DNA methylation patterns. Game theory predicts that phenotypic heterogeneity can facilitate bacterial adaptation to hostile or unpredictable environments, serving either as a division of labor or as a bet hedging that anticipates future challenges. Experimental observation confirms the existence of both types of strategies in the bacterial world.
康拉德·沃丁顿的表观遗传景观是多细胞生物发育的一种视觉隐喻，适用于描绘细菌细胞表型变体的形成。导致形态变化的细菌分化实例已为人所知数十年。此外，细菌群体中存在缺乏形态变化的表型细胞变体，荧光蛋白技术和单细胞分析的出现揭示了大量此类实例。细胞特异性基因表达模式可能起源于随机事件，也可能是程序性事件。当细胞间的表型差异具有遗传性时，细菌谱系就会形成。将表观遗传状态传递给子细胞的机制可能具有截然不同的复杂程度，从简单反馈回路的传播到复杂DNA甲基化模式的形成。博弈论预测，表型异质性可促进细菌适应恶劣或不可预测的环境，要么作为一种分工方式，要么作为一种应对未来挑战的风险对冲策略。实验观察证实了细菌世界中这两种策略的存在。
