Dating algal origin using molecular clock methods.

Algae and plants are the dominant primary producers on our planet and define an evolutionarily diverse group of taxa (Graham and Wilcox 2000). Despite their importance, dating algal origin is frustrated by a limited fossil record (Knoll 1992). Recent molecular phylogenetic trees place algae near the base of the eukaryotic tree of life (e.g., Baldauf et al. 2000, 2003; Nozaki et al. 2003). This suggests that endosymbiosis, the process that gave rise to algal plastids (Bhattacharya and Medlin 1995), was an ancient and fundamental force in eukaryotic evolution. To estimate the date of the cyanobacterial primary Dating Algal Origin Using Molecular Clock Methods