Tverskoi Denis, Gavrilets Sergey
National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996, USA; Center for the Dynamics of Social Complexity, University of Tennessee, Knoxville, TN 37996, USA; International Center of Decision Choice and Analysis, Higher School of Economics, Moscow 101000, Russian Federation.
National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996, USA; Center for the Dynamics of Social Complexity, University of Tennessee, Knoxville, TN 37996, USA; Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA; Department of Mathematics, University of Tennessee, Knoxville, TN 37996, USA.
J Theor Biol. 2022 Feb 7;534:110964. doi: 10.1016/j.jtbi.2021.110964. Epub 2021 Nov 25.
Division of labor exists at different levels of biological organization - from cell colonies to human societies. One of the simplest examples of the division of labor in multicellular organisms is germ-soma specialization, which plays a key role in the evolution of organismal complexity. Here we formulate and study a general mathematical model exploring the emergence of germ-soma specialization in colonies of cells. We consider a finite population of colonies competing for resources. Colonies are of the same size and are composed by asexually reproducing haploid cells. Each cell can contribute to activity and fecundity of the colony, these contributions are traded-off. We assume that all cells within a colony are genetically identical but gene effects on fecundity and activity are influenced by variation in the microenvironment experienced by individual cells. Through analytical theory and evolutionary agent-based modeling we show that the shape of the trade-off relation between somatic and reproductive functions, the type and extent of variation in within-colony microenvironment, and, in some cases, the number of genes involved, are important predictors of the extent of germ-soma specialization. Specifically, increasing convexity of the trade-off relation, the number of different environmental gradients acting within a colony, and the number of genes (in the case of random microenvironmental effects) promote the emergence of germ-soma specialization. Overall our results contribute towards a better understanding of the role of genetic, environmental, and microenvironmental factors in the evolution of germ-soma specialization.
劳动分工存在于生物组织的不同层面——从细胞群体到人类社会。多细胞生物中劳动分工最简单的例子之一是生殖细胞与体细胞的特化，它在生物体复杂性的进化中起着关键作用。在此，我们构建并研究了一个通用数学模型，以探索细胞群体中生殖细胞与体细胞特化的出现。我们考虑有限数量的群体竞争资源。群体大小相同，由无性繁殖的单倍体细胞组成。每个细胞都能对群体的活性和繁殖力做出贡献，这些贡献存在权衡。我们假设群体内的所有细胞基因相同，但基因对繁殖力和活性的影响受单个细胞所经历的微环境变化影响。通过分析理论和基于进化主体的建模，我们表明体细胞功能与生殖功能之间权衡关系的形状、群体内微环境变化的类型和程度，以及在某些情况下涉及的基因数量，是生殖细胞与体细胞特化程度的重要预测指标。具体而言，权衡关系凸度的增加、群体内作用的不同环境梯度的数量以及基因数量（在随机微环境效应的情况下）会促进生殖细胞与体细胞特化的出现。总体而言，我们的结果有助于更好地理解遗传、环境和微环境因素在生殖细胞与体细胞特化进化中的作用。
