David Baltimore was born in New-York in 1938. He studied at the Massachusetts Institute of Technology and the Rockefeller Institute where he received his doctorate. In 1965, Baltimore began research on the polio virus at the Salk Institute in California. While there, he discovered the way in which the virus replicates its genetic information found in the form of RNA.

In 1968, Baltimore moved to MIT and began studying other RNA viruses known to cause cancer in animals. He was surprised to find that they did not contain the enzyme necessary for their replication. According to the prevailing theory of the time, the transition from DNA to RNA is a one-way process. Baltimore found that with the aid of the enzyme “reverse transcriptase”, the viruses could change the process and build molecules of DNA on a RNA template.

Baltimore was awarded the 1975 Nobel prize for physiology and medicine, jointed with Renato Dulbecco and Howard Temin, “for their discoveries concerning the interaction between tumor viruses and the genetic material of the cell”. The work of the three researchers forged a link between two theories; the first claims that cancerous cells undergo genetic change due to mutation and the second holds that viruses can cause cancer.

The discovery of the “reverse transcriptase” accelerated the progress being made in the fields of molecular biology and genetic engineering, thus expanding an understanding of the replicating mechanism of retroviruses, including the AIDS virus.