The plastid-encoded psbA gene in the dinoflagellate Gonyaulax is not encoded on a minicircle

In all dinoflagellate species studied to date, the plastid genome is highly reduced, with many genes normally found in the plastid genome found instead encoded by the nucleus. Furthermore, those genes still remaining in the plastid are found as primarily single gene minicircles whose size is typically only 2–3 kb. We show here that the plastid genome architecture in the dinoflagellate Gonyaulax polyedra is unusual for this class of organism. In particular, the psbA gene is associated with DNA of roughly 50–150 kb and appears to have an unusually high complexity.