美国乔治亚理工学院William C. Ratcliff等研究人员合作实现宏观多细胞性的从头演化。2023年5月10日，《自然》杂志在线发表了这项成果。
研究人员表示，虽然早期的多细胞谱系必然是从相对简单的细胞群开始的，但对它们如何成为能够持续进行多细胞演化的达尔文实体知之甚少。
研究人员通过一个多细胞性长期演化实验来研究了这个问题，即在雪花酵母（Saccharomyces cerevisiae）模型系统中选择更大的群体规模。鉴于氧气限制的历史重要性，研究人员正在进行的实验包括三种代谢处理——厌氧、强制好氧和混合营养酵母。经过600轮的选择，厌氧处理组中的雪花酵母演化成了宏观的，变得大约2×104倍大（大约毫米级），生物物理上大约104倍的坚韧，同时保留了克隆的多细胞生命周期。这是通过生物物理适应性发生的——越来越长的细胞的演化，最初减少了细胞包装的应变，然后促进了分支的纠缠，使细胞群即使在许多细胞键断裂后也能保持在一起。相比之下，在低氧条件下竞争的雪花酵母仍然是微观的，只演化到大约六倍大，这强调了氧气水平在多细胞大小演化中的关键作用。总之，这项研究为正在进行的个体演化过渡提供了独特的见解，并显示了简单的细胞群如何通过渐进但持续的多细胞演化克服基本的生物物理限制。
附：英文原文
Title: De novo evolution of macroscopic multicellularity
Author: Bozdag, G. Ozan, Zamani-Dahaj, Seyed Alireza, Day, Thomas C., Kahn, Penelope C., Burnetti, Anthony J., Lac, Dung T., Tong, Kai, Conlin, Peter L., Balwani, Aishwarya H., Dyer, Eva L., Yunker, Peter J., Ratcliff, William C.
Issue&Volume: 2023-05-10
Abstract: While early multicellular lineages necessarily started out as relatively simple groups of cells, little is known about how they became Darwinian entities capable of sustained multicellular evolution1,2,3. Here we investigate this with a multicellularity long-term evolution experiment, selecting for larger group size in the snowflake yeast (Saccharomyces cerevisiae) model system. Given the historical importance of oxygen limitation4, our ongoing experiment consists of three metabolic treatments5—anaerobic, obligately aerobic and mixotrophic yeast. After 600 rounds of selection, snowflake yeast in the anaerobic treatment group evolved to be macroscopic, becoming around 2×104 times larger (approximately mm scale) and about 104-fold more biophysically tough, while retaining a clonal multicellular life cycle. This occurred through biophysical adaptation—evolution of increasingly elongate cells that initially reduced the strain of cellular packing and then facilitated branch entanglements that enabled groups of cells to stay together even after many cellular bonds fracture. By contrast, snowflake yeast competing for low oxygen5 remained microscopic, evolving to be only around sixfold larger, underscoring the critical role of oxygen levels in the evolution of multicellular size. Together, this research provides unique insights into an ongoing evolutionary transition in individuality, showing how simple groups of cells overcome fundamental biophysical limitations through gradual, yet sustained, multicellular evolution.
DOI: 10.1038/s41586-023-06052-1
Source: https://www.nature.com/articles/s41586-023-06052-1
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
