You've probably seen agar plates, if you smear a solution that's contaminated with bacteria on it, then that bacteria will grow on this agar rich medium and you'll get many, many copies of the bacteria that you've smeared at low density onto the plate.

你们大概见过琼脂培养基,如果将有细菌的溶液涂抹在培养基上,细菌就会在富含琼脂的培养基上生长,你会得到许多许多细菌,即使你只涂抹了低浓度溶液

耶鲁公开课 - 生物医学工程探索课程节选

The answer is it will want to reform with itself, and if I have these in solution then how many reform with itself and how many reform with the molecule I'm interested probably depends on the relative concentrations of both in the solution and what conditions I have it at.

答案是质粒有可能会自己闭合,如果质粒和我感兴趣的DNA片段,都在溶液里那有多少质粒会自己合上,有多少与我感兴趣的DNA重组呢,这大概取决于两者在溶液里的相对浓度,和我让溶液处在什么条件下

耶鲁公开课 - 生物医学工程探索课程节选