Dinoflagellates are enigmatic protists with odd nuclear features, interesting plastid gene arrangements and a proclivity for endosymbiotic relationships. Relatively little molecular work has been done on Dinoflagellates, and only a handful of genes have been characterized in these organisms. We have begun an Expressed Sequenced Tag (EST) project with the aim of collecting plastid targeted but nuclear encoded genes from peridinin-containing dinoflagellates. This provides an opportunity to understand the integration of endosymbiont genes into the host cell. Our sequencing effort has produced about one thousand unique ESTs from a Gonyaulax polyedra cDNA library obtained from David Morse. Of the 1535 total ESTs (72% > 400 b.p.) 466 sequences were identifiable by BLAST with a bitscore above 50. The most abundant transcript is the peridinin-chlorophyll binding protein, which constituted 3% of the clones. More recently we began sequencing from an Amphidinium carterae cDNA library made in our laboratory. This provides insight into expression patterns and is a resource for other workers in the field. Several clearly identifiable plastid genes have been found and preliminary analysis confirms the chromophyte, and therefore, tertiary origin of the peridinin plastid.

Key words: chromophyte algae, Dinoflagellates, EST, plastid evolution