Abstract：Genome RNA was extracted from bone marrow of pig (Duroc×Landrace× Yorkshire) and antimicrobial peptide PMAP-37 mRNA was amplified using RT-PCR. A DNA fragment about 282 bp in length was obtained and the PCR product was cloned into pGEM-T vector. The PMAP-37 gene was isolated and sequenced from the screened positive clones. Result of sequence analysis showed that this fragment was the partial sequence of PMAP-37 cDNA and coded 167 amino acid residues. The gene homology of the obtained fragment compared with that of reported PMAP-37 gene sequence in bone marrow of porcine was up to 98%. Based on the PMAP-37 gene clone, an optimal semi-quantitative RT-PCR method was successfully constructed. Using 18S rRNA as inner control, the difference of PMAP-37 gene expression at different avoirdupois of pig was researched, which increased from new born to 20 kg, decreased from 20 to 40 kg, increased from 40 to 60 kg and decreased again at the stage of 60 to 90 kg.
