The comparison of meq gene sequences of different pathotypes of marek ' s disease virus meq genes of different pathotypes of marek ' s disease virus ( mdv ) were amplified , in the whole opening reading frame ( orf ) by polymerase chain reaction ( pcr ) technique , sequenced and compared with the published sequence of ga strain ( representing vmdv ) . cvi988 / rispens and 814 , commercial vaccine strains popularly used worldwide and in china respectively ; 648a , representing very virulent plus ( vv + mdv ) and 6 field isolates , originated from guangxi commercial chickens with visceral lymphomas and vaccine breaks , representing high pathogenic ( hpmdv ) and two of them ( g2 and n ) were proved to be vvmdv , were used 本研究通過三個方面進行了研究,取得了如下主要實驗結果: 1mdv不同致病型( pathotypes )毒株meq基因序列的比較研究應用pcr技術擴增了不同致病型mdvs ,即國際通用型疫苗毒cv1988 rispens株和中國特有的疫苗毒814株、特超強毒648a株( vv + mdv )以及6個廣西分離到的野毒株共9個毒株的meq基因,進行核苷酸序列的測定并與標準強毒ga株( vmdv )進行核苷酸和氨基酸序列的比較。