The origin of plastids (chloroplasts) by endosymbiosis stands as one of the most important events in the history of eukaryotic life. The genetic, biochemical, and cell biological integration of a cyanobacterial endosymbiont into a heterotrophic host eukaryote approximately a billion years ago paved the way for the evolution of diverse algal groups in a wide range of aquatic and, eventually, terrestrial environments. Plastids have on multiple occasions also moved horizontally from eukaryote to eukaryote by secondary and tertiary endosymbiotic events. The overall picture of extant photosynthetic diversity can best be described as “patchy”: Plastid-bearing lineages are spread far and wide across the eukaryotic tree of life, nested within heterotrophic groups. The algae do not constitute a monophyletic entity, and understanding how, and how often, plastids have moved from branch to branch on the eukaryotic tree remains one of the most fundamental unsolved problems in the field of cell evolution. In this review, we provide an overview of recent advances in our understanding of the origin and spread of plastids from the perspective of comparative genomics. Recent years have seen significant improvements in genomic sampling from photosynthetic and nonphotosynthetic lineages, both of which have added important pieces to the puzzle of plastid evolution. Comparative genomics has also allowed us to better understand how endosymbionts become organelles.

中文翻译：

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质体进化的基因组见解。

内共生质体（叶绿体）的起源是真核生物生活史上最重要的事件之一。大约10亿年前，将蓝细菌内共生体整合到异养宿主真核生物中的遗传，生物化学和细胞生物学整合为在广泛的水生环境以及最终的陆生环境中进化各种藻类铺平了道路。通过次生和三次共生共生事件，质体在多种情况下也从真核生物水平移动到真核生物。现有光合作用多样性的总体描述可以最好地描述为“斑块状”：质体世系分布在真核生物的生命树上，分布在异养群体中。藻类不构成单一种类的实体，并且了解如何以及多久 质体在真核树上从一个分支移到另一个分支，仍然是细胞进化领域中最基本的未解决问题之一。在这篇综述中，我们从比较基因组学的角度概述了质体的起源和传播的最新进展。近年来，从光合和非光合谱系的基因组采样中取得了显着进步，这两者都为质体进化之谜增添了重要意义。比较基因组学还使我们能够更好地了解共生共生体如何变成细胞器。我们从比较基因组学的角度概述了质体的起源和传播方面的最新进展。近年来，从光合和非光合谱系的基因组采样中取得了显着进步，这两者都为质体进化之谜增添了重要意义。比较基因组学还使我们能够更好地了解共生共生体如何变成细胞器。我们从比较基因组学的角度概述了质体的起源和传播方面的最新进展。近年来，从光合作用和非光合作用谱系的基因组采样中取得了显着进步，这两者都为质体进化之谜增添了重要内容。比较基因组学还使我们能够更好地了解共生菌如何变成细胞器。