The Oxford-AstraZeneca vaccine against Covid-19 was built on the principle of stitching together DNA from two viruses, one to enable the vaccine to enter cells and the other to provoke an immune response.
In 1972 Paul Berg, who has died aged 96, became the first person to combine the DNA of two organisms in this way. Recombinant DNA has become a fundamental tool of biomedical research and drug discovery, making it possible to grow drugs such as human insulin in bacteria as well as to develop tailor-made vaccines.
