Isolation and purification of modified yacs from yeast strain have been carried out by pulsed - field gel electrophoresis . the modified yacs are expected to generate plant artificial chromosome after being transferred into arabidopsis protoplast by liposome - mediated method 用脉冲电泳将经过同源重组的修饰的yac克隆分离出来通过脂质体转化植物的原生质体,希望得到在植物细胞中稳定存在的植物人工染色体。