Recombinant DNA molecules are formed through genetic recombination techniques in the laboratory by combining DNA from multiple sources to create new sequences not found in nature. This is possible because DNA shares the same chemical structure across all organisms but differs in nucleotide sequence. Recombinant DNA was first proposed in the 1970s and early successful experiments were published in 1972-1973. Stanford University filed one of the earliest patents on the technology. Some of the earliest commercial applications included recombinant human insulin and growth hormone.