Molecular cloning is the amplification of a defined DNA sequence to arbitrarily high copy number by inserting it into a self-replicating vector and delegating replication to a host organism, rather than the duplication of a whole organism. The canonical route begins with isolating the mature messenger RNA of a gene of interest and reverse-transcribing it into complementary DNA (cDNA) — an intron-free, exon-only representation of the coding sequence — which is then ligated into a plasmid bearing a selectable marker, introduced into bacteria by transformation, and enriched by selective pressure so that only vector-bearing cells propagate. This concept belongs to molecular biology and recombinant DNA technology, and it operationalizes the central dogma in reverse (RNA to DNA) while providing the foundational technique on which gene expression analysis, sequencing, and protein production in the discipline depend.
Molecular cloning is the amplification of a defined DNA sequence to arbitrarily high copy number by inserting it into a self-replicating vector and delegating replication to a host organism, rather t…