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TY - JOUR AU - Palenik, B. AU - Haselkorn, R. PY - 1992 DA - 1992/01/01 TI - Multiple evolutionary origins of prochlorophytes, the chlorophyllb-containing prokaryotes JO - Nature SP - 265 EP - 267 VL - 355 IS - 6357 AB - PROCHLOROPHYTES are prokaryotes that carry out oxygenic photosynthesis using chlorophylls a and b, but lack phycobili-proteins as light-harvesting pigments1. These characteristics distinguish them from cyanobacteria, which contain phycobiliproteins, but no chlorophyll b. Three prochlorophyte genera have been described: Prochloron1–3,Prochlorothrix4andProchlorococcus5,6. The prochlorophytes share their pigment characteristics with green plant and euglenoid chloroplasts, which has led to a debate on whether these chloroplasts may have arisen from an endosymbiotic prochlorophyte rather than a cyanobacterium2,7. Molecular sequence data, including those presented here based on a fragment of the rpoCl gene encoding a subunit of DNA-dependent RNA polymerase, indicate that the known prochlorophyte lineages do not include the direct ancestor of chloroplasts8–11. We also show that the prochlorophytes are a highly diverged polyphyletic group. Thus the use of chlorophyll b as a light-harvesting pigment has developed independently several times in evolution. Similar conclusions have been reached in parallel studies using 16S ribosomal RNA sequences12. SN - 1476-4687 UR - https://doi.org/10.1038/355265a0 DO - 10.1038/355265a0 ID - Palenik1992 ER -