Intertwined strands of DNA molecules give rise to every form of life imaginable. Biological building blocks begin to assemble when the strands briefly unwind and are transcribed into a complementary single string of RNA – a molecular message which is in turn translated into particular proteins. This DNA to RNA conversion was long thought to be an exclusively one-way process but in 1970 David Baltimore – born on this day in 1938 – discovered an enzyme that does the opposite. Present in certain viruses, this reverse transcriptase molecule enables single strands of RNA to produce DNA, which can then integrate with and alter the host cell in a process called transformation. This mechanism can cause cancers, and underlies how HIV replicates. Baltimore shared a Nobel Prize for his role in the discovery, made vital contributions across immunology and virology, and transformed the careers of countless scientists under his tutelage.
Written by Anthony Lewis
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.