Sequence analysis of the plastid rDNA spacer region of the chlorophyll c-containing alga Cryptomonas phi.

A 0.8 kb AvaI/SmaI fragment of the plastid genome of the chlorophyll c-containing alga Cryptomonas phi encompassing the rRNA spacer region and flanking genes has been cloned and sequenced. The spacer region between the 16S and 23S rRNA genes is 275 base pairs long, one of the shortest yet reported, and it contains uninterrupted genes for tRNA(Ile) and tRNA(Ala) separated by only two base pairs. The coding regions for tRNAs and rRNAs have been compared with those from cyanobacteria, land plants and other algae and the possible evolutionary relationships discussed.