Molecular Cloning Of The DNA Sequence Of Activin β_A Subunit Gene Mature Peptides From Panda And Related Species And Its Application In The Research Of Phylogeny And Taxonomy

Activin,which is included in the transforming growth factor-β (TGF β) superfamily of proteins and receptors, is know to have broad-ranging effects in the creatures. The mature peptide of P A subunit of this gene, one of the most conserved sequence, can elevate the basal secretion of follicle-stimulating hormone (FSH) in the pituitary and FSH is pivotal to organism's reproduction. Reproduction block is one of the main reasons which cause giant panda to extinct. So it is necessary to clone the sequence of Activin P A subunit gene mature peptides from panda and related species. This work is promising in the research of giant panda reproduction block and the result can also be employed in the investigation of the phylogeny and taxonomy of panda and related animals.The sequence of Activin 3 A subunit gene mature peptides has been successfully amplified from giant panda ,lesser panda and malayan sun bear's genomic DNA by using polymerase chain reaction (PCR) with a pair ofdegenerate primers. The PCR products were cloned into the vector pBlueScript+ ofEsherichia coli.Sequence analysis of Activin P A subunit gene mature peptides shows that the length of this gene segment is the same ( 359bp) and there is no intron in all three species. The sequence encode a peptide of 119 amino acid residue. The homology comparison demonstrate 93.9% DNA homology and 99% homology in amino acid among these three species. Both GENEBANK blast search result and restriction enzyme map reveal that the sequences of Activin 3 A subunit gene mature peptides of different species are highly conserved during evolution.Phylogeny analysis is performed with PHYLIP software package. Same phylogeny tree has been draw with three different methods, i.e. maximum parsimony method, genetic distance method and maximum likelihood method, respectively. The software analysis outcome is consistent with the donimant view that giant panda has closer relationship to the malayan sun bear than to lesser panda. Giant panda should be grouped into the bear family (Uersidae) with the malayan sun bear. As to the lesser panda, it would be better that this animal be grouped into the unique family (lesser panda family) because of great difference between the lesser panda and the bears (Uersidae) .