Technical Writing

A writing sample by Ben Ayer:

Fluorophore-DNA conjugates have revolutionized our ability to detect sequences amplified during the polymerase chain reaction. These exquisite molecules have only emerged through incremental advancements in DNA chemistry spanning many decades of research. Oligo manufacturing is now automated using solid-phase DNA synthesizers. Phosphoramidite chemistry permits precise modification of the DNA strand. Striking fluorophores and dark quenchers build into a single molecule both the mechanism of quenching and signal release.

Fluorescent-labeled DNA is thus an artifice, born on the bench-top of a laboratory rather than in a primordial tide-pool. Yet, this synthetic partnership is showing no sign of unraveling any time soon. In fact, methods of organic chemistry and biological wizardry have become even more entangled with each passing decade, producing new technologies that further augment our genetic acuity. With all of its sophistication it is important to not lose sight of the forest for the trees. The culmination of this technology is a remarkably elegant system: a beacon of light emitting from a transparent plastic tube, and illuminating our path toward a new world of molecular diagnostics.

As humanity marches into an increasingly global society, the need to rapidly diagnose will only intensify. Repeated outbreaks of infectious agents (SARS, Avian Flu Virus, drug-resistant tuberculosis) have highlighted the urgency of an early diagnosis and the consequences of delay. Many involved in health care argue that the spiraling costs of modern medicine would be best controlled by changing from a system based upon treatment to one based upon diagnosis.

It is easy to envision compact instruments that identify pathogens in a matter of hours rather than weeks and distinguish the strains causing infection. Cancers will be distinguished to guide patients to the most appropriate treatment. Outside of medicine, agricultural crops can be more carefully bred according to their desirable genetic signatures. Food processes should be continuously screened for the emergence of spoilage organisms. In fact, these new procedures have already been implemented and are now becoming widespread; they all rely on fluorescent-labeled DNA to produce an answer. With each tiny flicker of light glancing across subtle optical sensors, our understanding of biology is becoming further refined and the very fabric of society is changing.

Excerpt from The PCR Revolution: Basic Technologies and Applications. S.A. Bustin (ed.) Cambridge University Press (2009).