Department of Biology, The College of New Jersey, Ewing, NJ 08628, USA.
Biology Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.
Genes (Basel). 2023 Apr 19;14(4):941. doi: 10.3390/genes14040941.
The evolutionary transition from single-celled to multicellular individuality requires organismal fitness to shift from the cell level to a cell group. This reorganization of fitness occurs by re-allocating the two components of fitness, survival and reproduction, between two specialized cell types in the multicellular group: soma and germ, respectively. How does the genetic basis for such fitness reorganization evolve? One possible mechanism is the co-option of life history genes present in the unicellular ancestors of a multicellular lineage. For instance, single-celled organisms must regulate their investment in survival and reproduction in response to environmental changes, particularly decreasing reproduction to ensure survival under stress. Such stress response life history genes can provide the genetic basis for the evolution of cellular differentiation in multicellular lineages. The -like gene family in the volvocine green algal lineage provides an excellent model system to study how this co-option can occur. We discuss the origin and evolution of the volvocine -like gene family, including -the gene that controls somatic cell development in the model organism . We hypothesize that the co-option of life history trade-off genes is a general mechanism involved in the transition to multicellular individuality, making volvocine algae and the -like family a useful template for similar investigations in other lineages.
从单细胞到多细胞个体的进化转变要求生物体的适应性从细胞水平转移到细胞群体。这种适应性的重新分配是通过在多细胞群体中的两种特化细胞类型之间重新分配适应性的两个组成部分，即生存和繁殖来实现的：体细胞和生殖细胞。这种适应性重新分配的遗传基础是如何进化的？一种可能的机制是共现于多细胞谱系的单细胞祖先中的生活史基因。例如，单细胞生物必须根据环境变化调节其在生存和繁殖方面的投资，特别是在压力下减少繁殖以确保生存。这种应激反应生活史基因可以为多细胞谱系中细胞分化的进化提供遗传基础。在绿色藻类绿球藻属的-like 基因家族为研究这种共现如何发生提供了一个极好的模型系统。我们讨论了绿球藻属-like 基因家族的起源和进化，包括控制模式生物体细胞发育的基因。我们假设，生活史权衡基因的共现是向多细胞个体性转变的一种普遍机制，使绿球藻属和-like 家族成为其他谱系中类似研究的有用模板。
