How can sample carryover contamination be prevented in restriction digest?

Correct answer: By using a new sterile filter tip for each sample

Using a new sterile, preferably filter, tip for each sample prevents DNA or enzyme from one sample from being transferred to another. Therefore, option A is correct. Reusing the same tip is a major cause of carryover contamination. Exam tip: In DNA handling, change the tip whenever the sample or reagent is changed.