By Karina Bakshi

Genetic mutations are the basis of evolution, and even life itself. Without genetic mutations, then there would not be any complex life forms existing in this universe. We have always wondered what was the cause of this phenomenon, but recent research may have come up with a possible solution. 

Quantum mechanics was a scientific breakthrough stating how the universe is based on probability. A good way to think about this is through the thought experiment “Schrodinger’s Cat”. In this thought experiment, there is a box. Inside of that box, there is a living creature (It can be anything, but a cat is generally used). In the experiment, there is radioactive material inside of the box along with a Geiger counter. There is a chance that the radioactive material will emit an alpha particle that may hit the Geiger counter. If it does, then it will send a signal to a hammer, which will smash a jar of poisonous material, killing the cat. According to quantum mechanics, the cat is both dead and alive at the same time! This is because of the uncertainty principle, which states that there is no definitive way of knowing a particle’s position and velocity. The more we know about a particle’s position, the less we know about its velocity, and vice versa. This idea can be taken even further. According to the uncertainty principle, everything that could have happened has happened as every particle could have been anywhere. This can be interpreted as there being an infinite number of parallel universes! 

Now let’s go back to Schrodinger’s cat. This means that the radioactive atoms in the box are in a quantum superposition of being both decayed and not decayed. This also means that the cat is both dead and alive at the same time! It is only when an observer opens the box that they get entangled into the quantum system and it only goes to one state. 

But what does any of this have to do with genetic mutations? A quantum phenomenon known as proton tunneling can be a big factor of genetic mutation. This means that protons in DNA can keep changing positions in the DNA, which changes the hydrogen bridges that bind the double helix together. This may lead to some errors and changes when the DNA has to make copies of itself. This can change the way that the bases in the DNA get paired with each other. Usually the bases in DNA follow the structure of AT and GC being together, but sometimes, because of this proton tunneling, they can mix with each other. However, due to computational limitations, only a small amount of the double helix was measured, so some of the observations may be incorrect. 

Classical mechanics also provides an explanation for this. The double helix is held together by relatively weak hydrogen bonds. When the temperature rises a lot, then it can cause the bonds to oscillate vigorously, which can make some of the atoms pop out of place. This happens because heat increases an atom’s kinetic energy, causing it to move. The oscillations let the hydrogen atoms form short bounds, but they usually go back to their original location. They usually stay in “stable” locations and only escape into “unstable” positions for brief periods of time. The type of hydrogen found in DNA (the most common isotope) only has 1 proton and no neutrons. When DNA gets formed, then these atoms lose their only electron, so when the protons transfer, they just move as a singular proton. This is called “proton transfer”. A recent study states that not all instances of protons moving in DNA are caused by proton transfer. This means that genetic mutation is both caused by proton transfer and proton tunneling, however proton tunneling causes more instances of this than proton transfer. 

Because of the uncertainty principle, these protons can do all sorts of things that they regularly shouldn’t be able to. They can even phase through walls! We need to know the amount of energy that the particles need to jump from stable positions to unstable positions to predict where and when the proton transfers may happen in DNA. This is called the “energy barrier” and the energy needed to transfer back into the stable state is the “reverse barrier’. According to the study, the energy barrier for proton transfer is much higher than the energy barrier for proton tunneling. The rate of proton tunneling is so much higher that if we ignore proton tunneling then the probability that the protons leap to opposite bases is almost 0. This means that proton tunneling plays a very large role in proton transfer. The reverse barrier between the AT pairs was also much lower than the GC pairs. This means that in the AT pairs if the atoms tunneled then they would go back very quickly. Meanwhile, in GC pairs they would stay in a relatively stable state for a longer time. If this happens shortly before the replication, then the proton could get stuck on the wrong side. This can cause errors, because when polymerase finds a proton in an unstable position then it can make errors with the copying. 

In addition to being a viable explanation to evolution, they can also be used to explain many diseases. These mutations can cause harmful diseases such as genetic disorders and multiple types of cancer. These discoveries can play a big part in finding cures for these diseases. Many of these diseases are severe and often result in death. Hopefully, we can use this information to find ways to cure these diseases as well.

Karina Bakshi is a 7th grader who enjoys learning and writing about science, especially space research. In her free time, she enjoys gaming. She plays the piano. She loves dogs and has one. Her main goal at The Ascent is to spread her ideas and opinions about science and tech.