用ＰＣＲ技术，从ＧＡ株马立克氏病病毒（ＭＤＶ）感染的成纤维细胞（ＧＥＦ）基因组ＤＮＡ中扩增出ＭＤＶ糖蛋白Ｄ（ｇＤ）抗原基因片段的约１３００ｂｐ编码序列，将该ｐｃＲ扩增的产物于ＥｃｏＲＩ和Ｋｐｎｌ位点克隆到ｐＵＣ１８质粒载体中，在以ｄｉｇｏｘｉｇｅｎｉｎ（ｄｉｇ）标记的ｇＤＰＣＲ产物作为探针，进行原位杂交初步筛选到阳性重组质粒克隆，再根据酶切分析筛选到含ＭＤＶｇＤ基因的重组质粒ｐ１８ＭｇＤ。将ｐ１８ＭｇＤ质粒ＤＮＡ用ｄｉｇ标记后，在Ｓｏｕｔｈｅｒｎｂｌｏｔ中，该探针能识别ＭＤＶ基因组ＤＮＡ的ＢａｍＨＩ－Ａ克隆中的Ａ片段ＤＮＡ。酶切位点分析表明，该ｇＤ克隆也和已发表的ＭＤＶ的ＲＢＩＢ株ｇＤ一样，不含有ＥｃｏＲⅠ、ＨｉｎｄⅢ、ＰｓｔⅠ、ＳｍａⅠ、ｐｖｕⅡ等酶切位点。证明该重组质粒是ＭＤＶｇＤ克隆。

arek's Disease Virus(MDV)glycoprotein D(gD) gene was amplificated from CEF ge-nomic DNA infected with MDV GA strain by polymerase chain reaction(PCR).PCR products ofthe gD gene were labeled with digoxigenin as porbes and they could only detect MDV-CEF ge-nomic DNA,MDV genomic DNA Bam HI-A fragment DNA by dot Not,but not uninfected CEFDNA,PCR products of the gD gene were cloned into pUC 18 plasmid,and recombinant plasmidswere screened by in situ hybridization with the probes of gD PCR products.The recombinantplasmids were also labeled with digoxigenin as probes.Two probes could detect gD PCR products,insert of recombinant plasmids,MDV genomic DNA BamHI-A fragment DNA by cross-hybridiza-tion in Southern blot.Restriction endonucleases analysis was used to identify the restriction sitesof the gD gene and polylinker of recombinant plasmid,and it showed that there were no sites of EcoRI、KpnI、HindⅢ、PstⅠ、Sma Ⅰ and PvuⅡ.It demonstrated that the recombinant plasmidcloned from MDV GA strain was gD clone.