Theories conflict on how life first evolved on Earth. But consensus suggests life began around hydrothermal vents under the oceans — where a cocktail of chemicals necessary for life fused simple organic compounds into complex ones, like DNA.
This process — called abiogenesis — involves water near the vents moving out into the ocean, where it cools, allowing DNA molecules to form simple cells.
However, there is much left to learn about the causes behind DNA mutation, and how the long haul of natural evolution began. The field of quantum biology investigates whether proton tunneling — a phenomenon of quantum physics — played a role in the spontaneous mutations inside DNA, and a recent paper published in the journal Physical Chemistry Chemical Physics suggests it does.
Human evolution could be explained by quantum physics
Proton tunneling is when a proton spontaneously disappears from one location, but then re-appears in a nearby location. The research team discovered that hydrogen atoms — which are incredibly light and act as bonds between the two strands of DNA's double-helix — can in some scenarios work like expanded waves, existing simultaneously in more than one place.
This DNA-level proton tunneling would lead to atoms sometimes showing up in the wrong strand of DNA — like genetic whack-a-mole — eventually leading to mutations.
The lifetime of these mutations is not long, but the research team found that they can persist through DNA replication inside cells — and might create health issues.
More research needed to study how quantum tunneling propagates
Typically, a human body's defense systems gather and fix genetic mutations. But when the system breaks down, misordered nucleotides can lead to health conditions, like cancer.
"Many have long suspected that the quantum world — which is weird, counter-intuitive and wonderful — plays a role in life as we know it," said Marco Sacchi, project lead of the study and Royal Society University Research Fellow at the Univesity of Surrey, in a blog post. "While the idea that something can be present in two places at the same time might be absurd to many of us, this happens all the time in the quantum world, and our study confirms that quantum tunneling also happens in DNA at room temperature."
"There is still a long and exciting road ahead of us to understand how biological processes work on the subatomic level, but our study — and countless others over the recent years — have confirmed quantum mechanics are at play," said Louie Slocombe, co-author of the study and a doctoral student at the Leverhulme Quantum Biology Doctoral Training Center, in the blog post. "In the future, we are hoping to investigate how tautomers produced by quantum tunneling can propagate and generate mutations."
Quantum tunneling could have played a role in early evolution
Another study from 2020 found that quantum tunneling can take roughly 0.62 milliseconds — although this involved a cloud of rubidium atoms and a laser beam.
While this doesn't mean quantum tunneling created life as we know it, it does shed light on the role quantum biology might play on the evolutionary path of life on Earth. At the right (or wrong) time and place, a wayward hydrogen atom in DNA could alter the course of an entire species — possibly driving highly-endangered species to extinction during environmentally challenging times (like after a major asteroid impact). But until more research is completed in the field of quantum biology, we can take solace in the poetry of knowing how fundamental forces like quantum mechanics potentially played a role during the very beginnings of life as we know it.