Recombinant DNA technology involves extracting and joining DNA from different sources. Key discoveries included DNA structure in 1953, DNA ligase in 1967, and restriction enzymes in 1970. Goals are to isolate, alter, and return genes to cells to understand and cure diseases. The procedure involves isolating, cutting, joining, and amplifying DNA using enzymes like restriction endonucleases and vectors like plasmids and cosmids. Techniques include gel electrophoresis, PCR, and hybridization. Applications are in agriculture, medicine, pharmacology, and more.