The origin of life is one of humanity’s greatest mysteries. For centuries, scientists have sought to understand how the complex systems that govern our world emerged from the simple chemistry of the early Earth. A crucial step in this process is the replication of genetic material, which would have been carried by RNA (ribonucleic acid) molecules before DNA and proteins later took over.

Chemists at UCL and the MRC Laboratory of Molecular Biology have made a groundbreaking discovery that brings us closer to understanding how life began. They’ve successfully recreated the conditions under which RNA might have replicated itself on early Earth, a key process in the origin of life.

The researchers used three-letter “triplet” RNA building blocks in water and added acid and heat, which separated the double helix structure that normally prevents RNA strands from replicating. By neutralizing and freezing the solution, they created liquid gaps between the ice crystals where the triplet building blocks could coat the RNA strands and prevent them from zipping back together, allowing replication to occur.

By repeating this cycle of changes in pH and temperature, which could plausibly occur in nature, the researchers were able to replicate RNA over and over again. This process produced RNA strands long enough to have a biological function and play a role in the origin of life.

The study’s lead author, Dr James Attwater, emphasized that replication is fundamental to biology. “In one sense, it is why we are here,” he said. “But there’s no trace in biology of the first replicator.”

The researchers believe that early life was run by RNA molecules, and their findings provide a possible explanation for how this process could have occurred before life began several billion years ago.

While the study focuses solely on the chemistry, the conditions they created could plausibly mimic those in freshwater ponds or lakes, especially in geothermal environments where heat from inside the Earth has reached the surface. However, this replication of RNA could not occur in freezing and thawing saltwater, as the presence of salt interferes with the freezing process and prevents RNA building blocks from reaching the concentration required to replicate RNA strands.

The origin of life is likely to have emerged out of a combination of RNA, peptides, enzymes, and barrier-forming lipids that can protect these ingredients from their environment. The researchers are uncovering clues about how life began, and their findings bring us closer to understanding this fundamental mystery.
In recent years, teams led by Dr John Sutherland and Professor Matthew Powner have demonstrated how chemistry could create many of the key molecules of life’s origin, including nucleotides, amino acids and peptides, simple lipids and precursors to some of the vitamins, from simple molecular building blocks likely abundant on the early Earth.

The latest study was supported by the Medical Research Council (MRC), part of UK Research and Innovation (UKRI), as well as the Royal Society and the Volkswagen Foundation.

The discovery of a root development gene older than root development itself is a fascinating find in the realm of plant biology. A recent study by Kobe University researchers has shed light on this phenomenon, providing insights into the fundamental evolutionary dynamic of co-opting and adapting mechanisms for new purposes.

The gene in question, called RLF, was previously found to be essential for lateral root development in Arabidopsis thaliana, a model plant commonly used in scientific research. However, it was surprising to discover that the equivalent gene in other plants, specifically liverworts (Marchantia polymorpha), is also involved in organ development.

Liverworts are ancient land plants that lack proper roots, but they do have their own version of the RLF gene. The Kobe University researchers studied this gene’s function and compared it to its Arabidopsis counterpart. They found that liverworts lacking RLF exhibit severe deformations in various organs, demonstrating the gene’s crucial role in organ development.

Furthermore, the study showed that the Arabidopsis gene can perform its function in liverwort cells, and vice versa. This functional interchangeability between the two genes highlights their shared evolutionary history and significance in plant development.

The RLF gene produces a protein that belongs to the heme-binding proteins group, which may bind a molecule called “heme” involved in energy transfer within the cell. The discovery of this mechanism is significant, as it was previously unknown to be involved in organ development in plants.

This research has implications for our understanding of plant evolution and development. By studying how the RLF protein interacts with others, scientists can gain more insights into the evolution of plant organ development. As Kobe University researcher Hidehiro Fukaki notes, “The fact that RLF plays an important role in organ development since at least the dawn of land plants is an example of how evolution often co-opts existing mechanisms for new functions.”

This research was funded by various Japanese institutions and conducted in collaboration with researchers from several universities. The findings have been published in the journal New Phytologist, providing a valuable contribution to our understanding of plant biology and evolution.

The genetic code that governs every living organism is not always beneficial. Some parts of DNA act like parasites, relying on the host for survival while contributing little to its overall well-being. These “selfish” genes are called introners, and they have been found to play a significant role in the evolution of genetic complexity.

Researchers from the University of California, Santa Cruz, have conducted a study that proves introners are responsible for many of these selfish genes spreading within and between species. This discovery sheds light on how genomes evolved to become so complex and could potentially be leveraged in human health research.

Introners are non-coding DNA segments that must be removed before proteins can be produced. They have been found to exist in varying amounts across all animals, plants, fungi, and protists, and have managed to successfully replicate themselves and survive despite not serving an evolutionary function.

The researchers, led by Russ Corbett-Detig, senior author on the study and professor of biomolecular engineering at the Baskin School of Engineering, have spent years studying introns. They wanted to understand why these non-protein-coding bits of DNA are seen in different amounts across species and how they have managed to replicate themselves.

Their research has shown that introners are a type of transposable element, also known as “jumping genes,” that can move from one part of the genome to another. They have found evidence for 1,093 families of introners among the 8,716 genomes analyzed, suggesting that there are many kinds of introners capable of spreading introns through the genomes of various species.

One of the most significant findings of this study is the first direct evidence for horizontal gene transfer of introners. The researchers found eight examples of an introner hopping out of the genome of one species and settling into the genome of another unrelated species that mating could not explain. This phenomenon has been observed in species as diverse as sea sponges, marine protists, and fungi.

The researchers propose that introners may be hitchhiking on giant viruses to transfer between species. This would mean that these selfish genetic elements are using other selfish elements to spread themselves throughout the genome.

While this study provides valuable insights into the evolution of genetic complexity, it also highlights the potential risks associated with introners. The process of alternative splicing, which is crucial for creating different versions of proteins from a single gene, can lead to health problems if it breaks a gene. Many researchers are studying how alternative splicing can be studied to better understand genetic disease.

In conclusion, the discovery of introners and their role in spreading selfish genes within and between species has significant implications for our understanding of genome evolution and human health research. Further studies on these hidden parasites of our DNA could potentially lead to breakthroughs in the treatment of genetic diseases.