RNA, or ribonucleic acid, plays a vital role in how life functions, particularly in protein synthesis. A recent study suggests that RNA could have formed easily on Earth around 4.3 billion years ago, shedding light on the origins of life.
RNA is simpler than DNA, which carries the genetic code for all living organisms. It comes in three forms: messenger RNA (mRNA), which sends genetic instructions; ribosomal RNA (rRNA), which helps build proteins; and transfer RNA (tRNA), which synthesizes proteins from mRNA.
Scientists believe RNA likely formed before DNA. This idea aligns with the “RNA world” hypothesis, suggesting that early life forms used RNA to replicate and pass on their genetic material.
However, figuring out how RNA’s components came together has been tough. Chemists have often thought that certain compounds, like borates found in seawater, hinder the chemical reactions needed to form RNA. But a team led by Yuta Hirakawa from Tohoku University argues otherwise.
In their experiments, the researchers combined ribose (a sugar), phosphates, and four nucleobases (adenine, guanine, cytosine, and uracil) with borates and volcanic rock called basalt. They heated the mixture and allowed it to dry, simulating conditions found in early Earth’s underground aquifers. Surprisingly, they discovered that RNA formed, and borates actually aided the process by stabilizing ribose and supporting other reactions.
Moreover, discoveries from NASA’s OSIRIS-REx mission to the asteroid Bennu have revealed ribose, adding more evidence to the idea that RNA’s building blocks were present early in Earth’s history. This asteroid is thought to have delivered essential ingredients to our planet, possibly during a massive impact from a protoplanet similar in size to Vesta.
The team estimates that the RNA formation process happened only 200 million years after Earth’s formation, before the oldest signs of life were found in minerals dated at 4.1 billion years old. According to Hirakawa’s projections, if such impacts occurred on Mars, RNA could have formed there too, as borates have also been detected on the Red Planet.
Previously, RNA was only created in labs with human intervention, but this research marks the first time it has been produced in conditions simulating early Earth, albeit through controlled experiments. Some critics argue that mixing the ingredients in a lab is still a form of intervention.
Understanding RNA’s formation is significant. It could provide insights into how life started on Earth and potentially elsewhere in the universe. As RNA forms the foundation for many life processes, its early existence could speed up the emergence of simple organisms.
This research highlights the intricate processes leading to the origin of life, suggesting that the combination of cosmic events and Earth’s conditions might have played a crucial role. Discoveries like these keep pushing the boundaries of our understanding, revealing a universe full of possibilities.
For more insights on RNA and life’s origins, you can check the original study published in the Proceedings of the National Academy of Sciences.
