BACKGROUND The packaging, expression, and maintenance of nuclear genomes using histone proteins is a ubiquitous and fundamental feature of eukaryotic cells, yet the phylum Dinoflagellata has apparently abandoned this model of nuclear organization. Their nuclei contain permanently condensed, liquid crystalline chromosomes that seemingly lack histone proteins, and contain remarkably large genomes...

Recent analyses of the small subunit ribosomal DNA (srDNA) from dinoflagellate symbionts of cnidaria have confirmed historical descriptions of a diverse but well-defined clade, Symbiodinium, as well as several other independent symbiont lineages (Rowan 1991; Rowan and Powers 1992; Sadler et al. 1992; McNally et al 1994). Dinoflagellates also occur as intracellular symbionts in a number of pelag...

The order Noctilucales or class Noctiluciphyceae encompasses three families of aberrant dinoflagellates (Noctilucaceae, Leptodiscaceae and Kofoidiniaceae) that, at least in some life stages, lack typical dinoflagellate characters such as the ribbon-like transversal flagellum or condensed chromosomes. Noctiluca scintillans, the first dinoflagellate to be described, has been intensively investiga...