There are whole catalogs that you go to and buy restriction enzymes.

我们已经可以从整本的目录上,挑选购买限制性内切酶

耶鲁公开课 - 生物医学工程探索课程节选

If I cut up just DNA from the chromosome, what's called genomic DNA, then I'm going to have both exons and introns within the fragments that I create.

如果我切割的恰好是染色体上的,基因组DNA,那我切成的片段上,就会同时有外显子和内含子

耶鲁公开课 - 生物医学工程探索课程节选