Topic overview

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Cloning begins by isolating a target DNA fragment and preparing it for insertion into a vector. Restriction endonucleases cut DNA at specific sequences, producing sticky or blunt ends, and DNA ligase joins the insert to the vector. Vector choice depends on insert size and host; useful features include an origin of replication, a multiple cloning site, and markers for selecting or identifying clones. In blue-white screening, disruption of lacZ distinguishes recombinant colonies from empty vectors. The topic also surveys transformation methods, genomic and cDNA libraries, and specialized approaches such as PCR and TA cloning. For more flexible assembly, Gateway, Gibson, and Golden Gate methods support seamless or multi-fragment cloning. Expression vectors and site-directed mutagenesis extend cloning to protein production and functional studies.