[A research on Ig heavy chain constant region of five Acipenseridae]

Analyzed the immunoglobulin (Ig) heavy chain constant regions of Russian sturgeon (A. gueldenstaedtii); Sterlte sturgeon (A. ruthenus); Amur sturgeon (A. schrenckii); Chinese sturgeon (A. sinensis) and Great sturgeon (Huso huso) with molecular biology and bioinformatics methods. We cloned IgH nucleic acid sequences by RT-PCR using the specific primer, then determined the characteristics and functions of the amino acid sequences and plotted out the sequence into four sub-regions (CH1-CH4), of which CH4 sub-regions one another had the highest identity. According to the analysis of the variation expectation value (Kaa), species differentiation time (T) in the CH4 sub-region phylogenetic tree, we found that Chinese sturgeon and the theoretical common ancestor of the other five sturgeon form the first bifurcation of the tree, while, among the five left, Amur sturgeon and Huso sturgeon, Russian sturgeon and Siberian sturgeon, Siberian sturgeon (sequence from GenBank), Sterlte itself form another three bifurcations respectively. This result can clearly explain the relations of taxonomic status, geographical distribution and evolution among the species studied.