GENOTYPIC RELATIONSHIPS IN TRICHODESMIUM (CYANOPHYCEAE) BASED ON NIFHSEQUENCE COMPARISONS

The DNA sequence of a fragment of nifH was compared to natural populat ions of the marine cyanobacteria Trichodesmium thiebautii and T. eryth raeum from the Caribbean Sea and the unialgal culture Trichodesmium sp . NIBB 1067, which was isolated from the Kuroshio waters (Japan). Thro ugh replication of amplification, cloning, and sequencing four nucleot ides in a 359-bp fragment were identified that were identical in seque nce to Trichodesmium sp. NIBB 1067 and natural populations of T. eryth raeum but were distinctly different in sequence from T. thiebautii. Th e data indicate that Trichodesmium sp. NIBB 1067 is more closely relat ed to T. erythraeum than to T. thiebautii.