Fig. 1.

OtV6 branches basal to all other available Ostreococcus spp. viral genomes. ML phylogenetic tree of green algal viruses is inferred from a concatenated sequence alignment of 22 core proteins shared among these viruses (7,668 sites) under the LG+G+F model. The unrooted version of this tree is presented below the midpoint-rooted tree. A red circle indicates OtV6 branch; other colored circles represent the taxonomy of the viral hosts: green (Ostreococcus), purple (Bathycoccus), yellow (Micromonas), and white (chloroviruses, viruses of Chlorella, as outgroup clade). Node support was calculated from 1,000 nonparametric bootstrap replicates; only bootstrap values >90% are shown. (Scale bar represents the number of estimated substitutions per site.) The branch connecting the prasinoviruses to the chloroviruses was truncated for display.