Gene order comparisons between trebouxiophyte plastid genomes. Genomes are drawn to scale. Coloured boxes represent identity with genes found in Helicosporidium sp., grey-shaded boxes represent identity between genes found in Chlorella vulgaris and Prototheca wickerhamii, and open boxes represent genes found only in C. vulgaris. Segments of the C. vulgaris genome that have been completely lost in Helicosporidium are shown in call-out boxes above the remainder of the genome. Straight lines join the genomes at the center points of protein coding and rRNA genes. For orientation, the rRNA genes are indicated.