The experimental procedure that begins with a cloned segment of dna , or a protein sequence , and uses this knowledge to introduce programmed mutations ( through directed mutagenesis ) back into the genome in order to investigate gene and protein function 在已知dna克隆片段或蛋白質(zhì)序列上引導(dǎo)程序性的變異(通過直接誘變)并返回到基因組,來研究基因和蛋白質(zhì)功能的實驗方法。