Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Proc Biol Sci. 2019 Sep 11;286(1910):20191098. doi: 10.1098/rspb.2019.1098. Epub 2019 Sep 4.
Understanding how and why cells cooperate to form multicellular organisms is a central aim of evolutionary biology. Multicellular groups can form through clonal development (where daughter cells stick to mother cells after division) or by aggregation (where cells aggregate to form groups). These different ways of forming groups directly affect relatedness between individual cells, which in turn can influence the degree of cooperation and conflict within the multicellular group. It is hard to study the evolution of multicellularity by focusing only on obligately multicellular organisms, like complex animals and plants, because the factors that favour multicellular cooperation cannot be disentangled, as cells cannot survive and reproduce independently. We support the use of Saccharomyces cerevisiae as an ideal model for studying the very first stages of the evolution of multicellularity. This is because it can form multicellular groups both clonally and through aggregation and uses a family of proteins called 'flocculins' that determine the way in which groups form, making it particularly amenable to laboratory experiments. We briefly review current knowledge about multicellularity in S. cerevisiae and then propose a framework for making predictions about the evolution of multicellular phenotypes in yeast based on social evolution theory. We finish by explaining how S. cerevisiae is a particularly useful experimental model for the analysis of open questions concerning multicellularity.
理解细胞如何以及为何合作形成多细胞生物是进化生物学的一个核心目标。多细胞群体可以通过克隆发育（细胞分裂后附着在母细胞上）或聚集（细胞聚集形成群体）形成。这些形成群体的不同方式直接影响个体细胞之间的亲缘关系，进而影响多细胞群体内部的合作和冲突程度。仅关注像复杂动物和植物这样的强制性多细胞生物，很难研究多细胞性的进化，因为有利于多细胞合作的因素无法被区分，因为细胞不能独立生存和繁殖。我们支持使用酿酒酵母作为研究多细胞性进化最初阶段的理想模型。这是因为它可以通过克隆和聚集形成多细胞群体，并且使用一组称为“絮凝蛋白”的蛋白质来决定群体形成的方式，这使得它特别适合于实验室实验。我们简要回顾了酿酒酵母中多细胞性的当前知识，然后提出了一个基于社会进化理论预测酵母中多细胞表型进化的框架。最后，我们解释了酿酒酵母如何成为分析有关多细胞性的悬而未决问题的特别有用的实验模型。
