| Sequences of 18s rDNA ITS region in the StrainX2 of Heterosigma akashiwo collected from Jiaozhou bay of China was determined. Combined with 37 homologous sequences downloaded from GenBank, the aligned ITS sequences of H.akashiwo were 534 bp,of which 16 sites were variable, and 1 site were parsimony-informative. Similarity between sequences was 97%. The contents of A+T(47.8%) were less than those of G+C (52.2%). In the phylogenetic tree, all the algae strains were clustered，and genetic distances among genus were between 0.0000~0.0242. Genetic diversity was very low for all the H.akashiwo. The growth and reproduction of H.akashiwo was restricted by many environment factors and anthropogenic reasons, such as ships' ballast water had been the main way of its transmission. |
