N-methyl-N'-nitro-N-nitrosoguanidine and uv induced mutants of the dinoflagellate Crypthecodinium cohnii

Mutant strains were chemically induced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and UV irradiation. UV and NTG mutation rates were obtained that were both consistent with the organism being haploid. Three types of mutants were produced: strains deficient in both beta- and gamma-carotene, the only carotenoids found in the wild type; phenotypes include albinos (translucent, dull white, snow white) and cream-colored on agar as compared to the yellow-orange color of wild type colonies; strains requiring adenine, guanine or cytosine in addition to the minimal medium for growth; mutants that grow at a rate less than 40% of the wild type in minimal medium