Topic overview

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The process relies on molecular tools that cut, join, copy, or convert DNA. Restriction endonucleases recognize specific palindromic sequences and produce sticky or blunt ends; DNA ligase seals the backbone where vector and insert meet. Cloning vectors—including plasmids and larger or viral options—are chosen for features such as an origin of replication, selectable marker, and cloning site. After introduction into host cells, antibiotic selection and blue-white screening can help identify candidates. The topic also distinguishes cDNA libraries, made from mature mRNA, from genomic libraries, which include introns. Expression vectors support protein production, while PCR and site-directed mutagenesis aid cloning and sequence changes. Screening methods and restriction mapping or sequencing are used to assess candidate constructs.