| Comments |
"The relaxed molecular clock based on the 129 proteins was
calibrated by six time constraints spread over the phylogenetic
tree and defined within green plants, animals, and fungi. Credibility intervals at 95% indicated that the basal split between the
major eukaryotic kingdoms documented here occurred 950–1,259 Mya (mean 1,085), followed by their diversification in
200 Myr (Fig. 1). Plantae originated 892–1,162 Mya (mean
1,010), and red algae branched off 825–1,061 Mya (mean 928),
whereas stem land plants separated from green algae 662–812
Mya (mean 729). This suggests that the endosymbiosis of a
free-living cyanobacterium that led to primary plastids (surrounded by two membranes) occurred between 825 and 1,162
Mya (Fig. 1). Plastids surrounded by four membranes originated
from secondary endosymbiosis, in which a red alga was engulfed
and retained by a flagellate protist. This event probably happened along the branch leading to stramenopiles +
alveolates,
i.e., between 767 and 1,072 Mya, shortly after the primary
endosymbiosis (Fig. 1)" Mya=million years ago. For date of plastid endosymbiotic event of ~1 billion years ago see Kiefel 2006 PMID 17147999 p.159 2nd paragraph |