Abstract: Partial nucleotide sequences of 16S rRNA were amplified using PCR techniques from three species (Acipenser sinensis,Acipenser gueldenstaedtii,Polyodon spathula) of Acipenseriformes.With sequences from other six species in NCBI database,the genetic variability and phylogenetic relationship were tested among 9 species from 2 families and 5 genera of Acipenseriformes.29 nucleotide variable positions including 16 parsimony infomative positions and 13 singleton positions were detected in analyzed 514 bp length sequence which were defined among the species.Taken Polypterus ornatipinnis as outgroup,similar phylogenetic trees were constructed by MP and NJ method among these 9 species of Acipenseriformes.The results showed that the differentiation of family,subfamily and genus was consistent with traditional morphological classification.Additionally,there was no significant difference between Huso huso and sturgeon.It is worth noting that 3 branches from 6 species in sturgeon subfamily belonged to 3 geographical regions.Among them,Huso huso,Acipenser stellatus and Acipenser gueldenstaedtii were mainly distributed in the Black sea and the Caspian sea basin,Acipenser sinensis and Acipenser dabryanus in the northwest Pacific,China yangtze river and Korea,while Acipenser transmontanus in the eastern Pacific.

Key words: Acipenseriformes, mitochondrial DNA, 16S rRNA, phylogenetic tree