Cavalier-Smith T
Dept of Zoology, University of Oxford, UK.
Trends Plant Sci. 2000 Apr;5(4):174-82. doi: 10.1016/s1360-1385(00)01598-3.
Membrane heredity was central to the unique symbiogenetic origin from cyanobacteria of chloroplasts in the ancestor of Plantae (green plants, red algae, glaucophytes) and to subsequent lateral transfers of plastids to form even more complex photosynthetic chimeras. Each symbiogenesis integrated disparate genomes and several radically different genetic membranes into a more complex cell. The common ancestor of Plantae evolved transit machinery for plastid protein import. In later secondary symbiogeneses, signal sequences were added to target proteins across host perialgal membranes: independently into green algal plastids (euglenoids, chlorarachneans) and red algal plastids (alveolates, chromists). Conservatism and innovation during early plastid diversification are discussed.
膜遗传对于植物界（绿色植物、红藻、灰胞藻）祖先中叶绿体从蓝细菌独特的共生起源至关重要，对于随后质体的横向转移以形成更为复杂的光合嵌合体也至关重要。每次共生起源都将不同的基因组和几种截然不同的遗传膜整合到一个更复杂的细胞中。植物界的共同祖先进化出了用于质体蛋白输入的转运机制。在后来的次生共生起源中，信号序列被添加到跨宿主周质膜的靶蛋白上：分别进入绿藻质体（裸藻、绿胞藻）和红藻质体（囊泡虫类、色素体生物）。本文讨论了早期质体多样化过程中的保守性和创新性。
