Enzymes from hot springs, toxins from frogs, and the many, many medicinal uses of plants. Following our piece on zoonotic diseases, we explore how evolution has been a source of medical innovation.
Did you know that a crucial ingredient in the test to diagnose COVID-19 was discovered in a freshwater hot spring?
Actually, it’s even more significant than that. This compound (a type of enzyme named DNA polymerase) has also been used to test other emerging diseases like AIDS and SARS, and is the key ingredient in a technique which underlies modern genetics: the polymerase chain reaction (PCR).
The PCR was developed in the mid-1980s using a DNA polymerase developed from bacteria Thermus aquaticus (named Taq DNA polymerase from T. aquaticus) found in a hot spring in Yellowstone National Park. Since then, biotechnology companies have produced a similar enzyme for PCR from bacteria living in deep-sea hydrothermal vents (Pfu DNA polymerase). These DNA polymerase enzymes have enabled medical scientists to take a small sample of virus DNA (for example, in a patient’s blood sample) and multiply it until it is big enough to detect and confirm a diagnosis. The PCR process requires a series of drastic temperature changes, and what made the discovery of Taq DNA polymerase so important was its ability to function despite the fluctuations to extreme temperatures – due to the extreme environments in which these bacteria had evolved.
A bacteria discovered in a hot spring within Yellowstone National Park in the United States was the key to a technique underpinning modern genetic science. Image: vladislav@munich/Flickr
Nature’s trial and error
The process of evolution – trial and error over millions of generations – means that all lifeforms which we share our planet with today have scraped their survival through long trials of adapting and readapting to their environments. The innovation that we find in the natural world is the basis of our study of chemistry and biology- without it, we lose a few billion years’ head-start.
Even though most of the innovations which inform medicine are chemicals like Taq DNA polymerase, it’s not just microscopic life like the bacteria Thermus aquaticus which has led to medicinal breakthroughs. Sometimes vertebrates can create extraordinary chemical innovations by becoming locked in an arms race… which is as exciting as it sounds.
An evolutionary arms race
A male Red-bellied newt (Taricha rivularis) in northern California. Newts in the Taricha genus (Pacific newts) possess the biotoxin tetrodotoxin and can be lethal to humans if consumed. Image: Seánín Óg
Pacific newts (from the genus Taricha which comprises four species of rough-skinned newt) can be found from southern Alaska to southern California. With their soft skin, slow gait and small size, these newts are perfect snacks for aquatic garter snakes. Like many am