A bacterial discovery at Yellowstone 55 years ago has been key to the development of PCR testing, the most reliable way to know whether someone has COVID-19.
National parks aren’t just fun places to vacation — they are also living laboratories for scientific research. In some cases, chance discoveries can have long-term benefits, as was the case more than five decades ago in one of the nation’s most famous parks.
In the mid-1960s, a microbiologist named Thomas Brock found himself fascinated with the bacteria that could survive in the superheated thermal pools at Yellowstone. His research focused on studying microorganisms in their natural environments, from tidal pools to lakes to soils. For about 10 years, his primary interest was studying geysers and thermal springs — which he saw for the first time on a trip to Yellowstone. The park both inspired and became a perfect setting for his work.
Brock collected samples in various parts of the park, gathering evidence that microbial life could exist in temperatures hotter than photosynthetic life forms could survive. In his research, he took samples from a large spring in the Lower Geyser Basin known as Mushroom Pool. Here, he and an undergraduate student, Hudson Freeze, isolated a microbe that could survive at nearly boiling temperatures. The single-celled microbe, now known, fittingly, as Thermus aquaticus, has since become an essential part of polymerase chain reaction (PCR) testing, because it remains stable at such extreme temperatures.
PCR testing is a process that scientists use to rapidly copy DNA, creating millions of replicas of a specific sample to study it. To do so, the DNA must be repeatedly heated and cooled in a process called thermal cycling. This cycling had once taken a great deal of time to perform, and the temperature fluctuations risked damaging the enzymes that would hold the DNA sequences together. But the little microbe in Mushroom Pool? Turns out it is very well-suited to survive thermal cycling and enable DNA copying without breaking down from all that heating and cooling — a natural advantage that living in a geyser prepares you for.
“My discovery of T. aquaticus and other high-temperature bacteria could not have been made without studies directly in the natural environment in Yellowstone National Park,” Brock said in a 1997 research paper detailing his 1966 discovery in the journal Genetics.
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The procedure has been valuable for years in prenatal testing, early diagnosis of diseases such as leukemia and lymphomas, genetic research, and forensic applications, including DNA testing from crime scenes, among many other uses. As valuable as the procedure is, it became all the more important as the coronavirus spread across the world in 2020, and PCR testing became a critical way of knowing who was exposed, saving lives during a time of global crisis.
Learn more about this fascinating discovery in this National Geographic article with more detail on Dr. Brock and his work, and how T. aquaticus is used to study the RNA samples in current COVID-19 testing.
About the author
Jennifer Errick Managing Editor of Online Communications
Jennifer writes, edits and moderates online content for NPCA.