KEY HIGHLIGHTS
- DNA Replication Insights: Researchers at the University of Helsinki uncovered a mechanism in DNA replication creating unique palindromic sequences.
- MicroRNA Gene Formation: The discovered palindromes can transform into microRNA genes, crucial for controlling the functionality of other genes.
- Unraveling Mistakes in DNA Copying: Scientists likened DNA copying to typing, identifying instances where copying backward (palindromes) occurs, revealing a new understanding of gene formation.
- Evolutionary Significance: The study, focusing on humans and primates, suggests this mechanism is widespread and explains the emergence of numerous microRNA genes in different species.
- Computational Analysis: Utilizing a specialized computer program, researchers traced gene history, demonstrating that entire palindromes can form through single mutation events.
- RNA Structural Insights: The research sheds light on RNA structures’ origin, helping to comprehend their functions and offering valuable insights into the evolutionary processes of genes.
Scientists at the University of Helsinki have made an groundbreaking discovery about how new genes come to be. They found a way that can create special DNA patterns and turn them into new genes, called microRNA genes.
The human genome has around 20,000 genes that build proteins. These genes are controlled by regulatory genes, including tiny ones that make 22-base pair microRNA molecules. While the number of genes usually stays the same, sometimes new genes appear over time, which intrigues scientists, similar to how biological life begins.
All RNA molecules need special base patterns to function properly. It’s hard for random mutations to create these patterns, even in simple microRNA genes. So, researchers at the Institute of Biotechnology, University of Helsinki, Finland, solved this puzzle. They found a way to instantly create complete DNA patterns, making new microRNA genes from sections of DNA that didn’t code for anything before.
MicroRNA Gene Origins: Helsinki Scientists Uncover Evolutionary Mechanism
Helsinki Scientists looked into mistakes that happen when DNA is copied, and they saw that some of these mistakes can lead to the formation of unique DNA patterns. These patterns, called palindromes, can then turn into microRNA genes. These genes are crucial because they help control how other genes work.
Before this discovery, scientists didn’t understand how these special DNA patterns appeared because it seemed very unlikely to happen by random mistakes. But the researchers in Helsinki figured it out.
They compared the process of copying DNA to typing on a keyboard, where each letter is copied one at a time. They found a way that can cause bigger mistakes during this copying process, kind of like when you copy and paste text from one place to another.
“We were especially interested in cases where the text was copied backward, creating a palindrome,” explained project leader Ari Löytynoja. She further added, “DNA is copied one base at a time, and typically mutations are erroneous single bases, like mis-punches on a laptop keyboard. We studied a mechanism creating larger errors, like copy-pasting text from another context. We were especially interested in cases that copied the text backwards so that it creates a palindrome.”
Scientists discovered that mistakes during gene replication, creating sequences that read the same backward and forward (palindromic sequences), can be helpful. These sequences can fold into structures resembling those in RNA molecules.
RNA biology expert Mikko Frilander acknowledged the importance of these findings for understanding RNA molecules’ structure and function.
“In an RNA molecule, the bases of adjacent palindromes can pair and form structures resembling a hairpin. Such structures are crucial for the function of the RNA molecules, and the discovery of a mechanism that can generate complete DNA palindromes sheds light on the origin of these structures,” said Frilander.
Scientists chose to study microRNA genes because they are small and uncomplicated. These genes are only a few bases long and need to fold into a specific shape to work properly.
Using a special computer program, the researchers studied gene history and analyzed how microRNA genes originated. They looked at different species’ genomes and found that entire palindromes could form through single mutation events. Postdoctoral researcher Heli Monttinen explained that this method allows for a very detailed examination of where the genes came from.
The team concentrated on humans and primates and found that this new mechanism could explain a significant number of new microRNA genes. They believe this mechanism is widespread and applies to other evolutionary lines.
Researchers in Helsinki have shown that a recently discovered mechanism can account for at least 25% of new microRNA genes in humans and other primates. Similar cases were found in other evolutionary branches, suggesting that this mechanism is widespread.
The process of developing new microRNA genes seems to be straightforward, and these new genes could have implications for human health. Heli Monttinen believes that the significance of this research goes beyond just understanding the basics of biological life – it has broader implications.
“The emergence of new genes from nothing has fascinated researchers. We now have an elegant model for the evolution of RNA genes,” she highlights.
The study focused on small regulatory genes, but the researchers think the results can apply to other RNA genes and molecules too. This groundbreaking research gives us insights into how new genes emerge and the fundamental principles of life. It opens up the chance to study the evolution of RNA genes and the development of more complex RNA structures and functions.
The study’s findings were published in the Proceedings of the National Academy of Sciences.
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Source(s): The Print; The Week
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