Libraries may be highly complex (as when cloning complete genomic DNA from an organism) or relatively simple (as when moving a previously cloned DNA fragment into a different plasmid), but it is almost always necessary to examine a number of different clones to be sure that the desired DNA construct is obtained.
As librarías poden ser moi complexas (como cando se fai a clonación do ADN xenómico completo dun organismo) ou relativamente simples (como cando se pasa un fragmento de ADN previamente clonado a un plásmido diferente), pero é case sempre necesario examinar varios clons diferentes para asegurarase de que se obtén o constructo de ADN desexado.