Membrane heredity and early chloroplast evolution

Membrane heredity was central to the unique symbiogenetic origin from cyano bacteria of chloroplasts in the ancestor of Plantae (green plants, red alga e, glaucophytes) and to subsequent lateral transfers of plastids to form ev en more complex photosynthetic chimeras, Each symbiogenesis integrated disp arate 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: independent ly into green algal plastids (euglenoids, chlorarachneans) and red algal pl astids (alveolates, chromists), Conservatism and innovation during early pl astid diversification are discussed.