【摘要】 基因工程中，重组ＤＮＡ时，当外源ＤＮＡ很小并与载体相差很大时，其目的重组子的筛选鉴定工作不仅量大，而且常规鉴定方法无法采用。本文针对此类重组子的鉴定方法作了探讨，提出了三级四步筛选鉴定法，即：质粒筛选、重组鉴定、目的重组鉴定和双酶切鉴定。该法不仅有效地解决了国内普通实验条件下含小插入片段重组子的鉴定问题，大大缩小鉴定范围，而且快速省耗的鉴定方法也为ｐＧＥＸ载体系统的更广泛应用提供了新的启示。更多还原

【Abstract】 When insertis moresmaller than vector that is very trouble to identify the recombination. We have succeeded to researcch the method of identifing recombination by three stages whichemploy four times. These are screening plasmid, identifing recombination and target recombination Which digested by one and tow restriction enzymes. This method is more rapidly and the consumption of enzyme can be decreased greatly.更多还原