A backbone technology in molecular biology is polymerase chain reaction (PCR) invented in 1983. Its inventor, Kary Mullis, PhD, was awarded the 1993 Nobel Prize in chemistry (shared with Michael Smith) for this now ubiquitous measurement method. “Mullis used the ‘diverse skills and diverse resources’ on hand at Cetus (where he worked) to create a new tool in an area for which he was not trained.” reference That’s quite an achievement.
The significance of the method can be appreciated in that the history of molecular biology is divided into pre-PCR versus post-PCR eras; this is because of the heightened ability to detect rare genomic sequences enabled by PCR.
Starting with a strand of DNA (RNA can be used to synthesize DNA, such as is needed to study the coronaviruses), small custom-designed stretches of DNA that are complementary to regions of the DNA region of interest are used to guide the synthesis of a copy of the region; this new strand becomes the template for another round of synthesis of the region. One copy becomes two; two become four; four become eight; eight become sixteen and so on. It’s a chain reaction driven by a polymerase enzyme which copies a single strand of DNA into its complementary strand; these strands are separated (actually, melted apart), and the reaction repeats. PCR amplifies DNA regions a million- to billion-fold. The method is generally highly quantitative, highly specific, and highly replicable in any lab with the right biochemicals and equipment (now off the shelf commodities). In fact, you could do this at home.
Discovery is all about seeing something new that was present all along but not detected (too weak a signal) or not discerned (indiscriminate from background) or not appreciated for its significance (didn’t know that it mattered). Amplifying the signal increases the likelihood of detection, but it may also create a lot of noise if the wrong stuff gets amplified.
I wonder whether we’d make faster progress if we chatted more about the stuff we are seeing in our discovery efforts (amplified the signal), and whether short bursts of debate and disagreements of meaning of the findings could help us separate signal from noise.
Poke someone today with what you’re seeing.
