Where did molecular biology come from?
The pioneers of molecular biology set out to understand life’s big picture by deciphering its chemical foundations. They fused traditionally separate branches of science and convinced the world that the big problems in biology were, and still are, problems of information.
During the first three decades of the twentieth century biology was changing fast. Cell biologists were using powerful microscopes to peer into cells and describe their minute inner structures. Geneticists had re-discovered Mendel’s laws of inheritance, penned in the 1860s, but then forgotten. Biochemists were making great strides in describing the characteristics of enzymes and other types of protein. They were also linking them together into complex metabolic pathways.
Despite this immense progress great gaps still yawned within and between these different disciplines. It was not at all clear how the finest structures seen down the microscope related to the chemical entities studied by the biochemists. Biochemists rarely stopped to wonder how genes related to the enzymes that they scrutinised in such detail. Geneticists didn’t know what genes were made from. They were even more clueless about how genes are passed down through the generations. What possible mechanism could explain the unbroken chain of inheritance that stretches back from you the reader to the planet’s first life forms that emerged over 3 billion years ago?
The pioneers of molecular biologists stared boldly into these holes in our knowledge. They set about patching them by borrowing insights from different fields and designing new tools and approaches of their own. The early twentieth century saw physical scientists outlining fundamental laws such as quantum mechanics and atomic theory. Buoyed by these leaps some biologists believed that equally deep laws might govern biological systems.
The American mathematician and science administrator Warren Weaver was a key figure in the establishment of molecular biology. It was Weaver who coined the term molecular biology itself, in 1938. He was one of the first to imagine what biology could gain from the new theoretical and infrastructural prowess of chemistry, physics and mathematics.
In 1933 he convinced America’s powerful Rockefeller Foundation to start funding biology in earnest. From 1933–1951 they sought out researchers willing to straddle traditional scientific boundaries and encouraged them to confront biological problems. Their call to arms was answered emphatically. In the following decades some of the biggest problems in biology were solved one by one, many by Rockefeller-supported scientists and those whom they influenced.
In 1940 George Beadle and Edward Tatum provided the first good evidence that genes tell cells exactly how to build proteins, the cell’s main do-ers and makers. They proved that genes are the fundamental unit of information in biology, an idea that remains unchallenged to this day. In 1944 Oswald Avery, Maclyn McCarty and Colin McLeod showed that genes are made from DNA, not protein as most researchers believed at the time. In their classic 1952 experiment Martha Chase and Alfred Hershey confirmed this beyond reasonable doubt.
From these pioneering endeavours stemmed Watson and Crick’s determination to solve the structure of DNA. They famously achieved their aim in 1953. Through the 1950s many more scientists joined the molecular cause. By 1966, the genetic code itself was solved and we saw exactly how genes control the building of proteins. The fact that humans use exactly the same code as parrots, polio and potatoes provides the most convincing support for Darwin’s key prediction that every living thing on Earth is related.
These foundational discoveries led to Francis Crick to propose the central dogma of molecular biology. This key hypothesis first presented by Crick in 1956 and re-stated more forcefully in 1970. The central dogma describes how the genetic information flows between genes (made from DNA), the intermediate molecules (made from RNA) and the proteins.
Subsequent decades of research have embellished, tweaked and challenged aspects of the central dogma, but it has always remained a touchstone for molecular biology research. Cells are not just bags of chemicals blindly reacting, they are highly ordered and highly programmed. The dogma put the flow and exchange of information firmly at the centre of the molecular biology endeavour.
With such a strong set of ideas at its core it is easy to see how molecular biology took root in the modern world. Through the 1960s and 70s governments, industry, universities and other funders gradually woke up to the new science of molecular biology. Edinburgh was at the forefront of this explosion in molecular biology. In 1965 they opened one of the world’s first university departments dedicated to the new science.
Molecular biology has blossomed into the dominant sector of biological research. The new wave of biologists have plugged many of the bigger gaps in our understanding of the molecular foundations of life. They’ve also given us tools to probe and manipulate living cells in ever more sophisticated ways. But the molecular biology revolution which started less than a century ago is still very much underway.
Originally published at moleculartinkering.wordpress.com on September 18, 2014.
