Mitochondrial DNA sequences of six sturgeon species and phylogenetic relationships within Acipenseridae

Studies on mitochondrial DNA variability amongst six sturgeon species reared in Italian aquaculture plants are reported. Restriction analysis by Rsal of mitochondrial cytochrome b and D-loop fragments amplified by PCR permitted identification of interspecific variations that would be suitable as markers for species diagnosis. Data obtained by partial sequencing of the cytochrome b gene, analyzed through maximum parsimony, neighbour joining, and UPGMA distance methods, revealed species clusters that support previous morpho-meristic and geographical data for sturgeon classification into sub-genera. According to our cluster analysis, the genera Acipenser and Huso are monophyletic. Moreover, these and previous cytogenetic data suggest that three 120-chromosome species (H. huso, H. dauricus and A. ruthenus) are at the base of sturgeon differentiation, which occurred through two different events of polyploidization.