Early evolution of cyanobacteria: investigation into evolutionary transition between non-oxygenic and oxygenic photosyntheses

蓝藻是地球上最早的光合作用生物，在生物史和环境史上都有着重要的影响。因此，阐明它们的演化是早期生命和地球研究的关键问题之一。基于光合作用器官的结构分析和分子系统发育研究，蓝藻通常被认为起源于非产氧型光合细菌，但它们的进化方式和时间尚不清楚。本研究旨在通过结合现代蓝藻在缺氧-缺氧界面下的生理和分子系统发育分析，结合环境和地质信息，揭示蓝藻的早期进化及其与地球环境变化的关系。

Cyanobacteria are the first oxygenic photosynthetic organisms on earth and have significant effects on organismic and environmental history. Elucidation of their evolution thus is one of key questions in the study of early life and earth. Based on structural analyses of photosynthetic apparatuses and molecular phylogenetic studies, cyanobacteria are generally considered to have originated from non-oxygenic photosynthetic bacteria: however, how and when they evolved has remained unclear.This study aimed at revealing early evolution of cyanobacteria and its relation to the earth's environmental change, through integration of physiological and molecular-phylogenetic analyses of modern cyanobacteria under the oxic-anoxic interface, with environmental and geological information.