Identification and transcription of transfer RNA genes in dinoflagellate plastid minicircles.

The dinoflagellate chloroplast genome is unique in that the genes are found on small circular DNA molecules carrying from one to three genes. In addition, only 14 of the typical chloroplast-located genes have so far been discovered on minicircles, while a number have been transferred to the nucleus. We have sequenced four new minicircles from the dinoflagellate Heterocapsa triquetra, three of which carry a single protein-coding gene (psbD, psbE, petD) and one that appears to be an "empty" circle.