In a groundbreaking scientific discovery, researchers have uncovered a fascinating new type of genetic entity called ‘obelisks’ that challenges our understanding of microscopic life. These tiny, mysterious structures are circular bits of genetic material that self-organize into rod-like shapes and have been found living inside bacteria in human mouths and guts.
The research team, led by Stanford biochemist Ivan Zheludev, stumbled upon these peculiar organisms while sifting through RNA databases containing genetic sequences from human samples. What makes obelisks truly remarkable is that they were completely unknown until this point, hiding in plain sight within the complex ecosystem of the human microbiome.
Preliminary findings suggest that obelisks are surprisingly common, with researchers discovering that they exist in approximately half of the world’s population. Most frequently found in the human mouth, they also appear in about seven percent of gut microbiomes. Despite their prevalence, scientists are still puzzled about how these entities spread and what role they play in human health.
What sets obelisks apart is their unique genetic structure. They contain one or two genes and have genomes composed of RNA loops that resemble viroids – tiny infectious agents typically found in plants. Remarkably, all discovered obelisks encode a distinctive protein called obulin, which is entirely unlike any protein previously documented.
Cell and developmental biologist Mark Peifer described the discovery as “insane,” highlighting the ongoing mystery surrounding these microscopic organisms. Are they potential threats or harmless passengers in our body’s bacterial ecosystems? Currently, scientists can only speculate about their ecological and evolutionary roles.
The research suggests that obelisks colonize bacterial cells in a manner similar to how viruses infect hosts. One specific example involves Streptococcus sanguinis, a common bacteria found in dental plaque, which hosts a particular type of obelisk. This discovery is particularly exciting because S. sanguinis can be easily cultured in laboratory settings, potentially allowing researchers to study how these entities survive and replicate.
Importantly, obelisks are classified as non-living organisms, much like viruses and viroids. They cannot eat, regenerate, or reproduce independently. Some researchers even propose that these tiny genetic entities might represent some of the oldest “life-like” forms on Earth, potentially playing a critical role in shaping biological diversity through evolutionary history.
While the immediate health implications remain unclear, scientists are intrigued by the potential impact obelisks might have on the human microbiome. They could be parasitic and harmful, or conversely, they might be completely benign or even beneficial to their bacterial hosts.
The research, published in the journal Cell, revealed an astonishing 30,000 distinct obelisk types that had previously gone unnoticed due to their unique characteristics. Long-term analysis indicates that a single obelisk type can inhabit a human host for approximately one year.
One fascinating parallel drawn by researchers is with Hepatitis D, a known viroid that can cause illness in humans. However, it remains uncertain whether obelisks possess similar pathogenic potential.
As with many scientific discoveries, this finding raises more questions than it answers. Future research will be crucial in understanding these mysterious genetic entities, their transmission methods, and potential implications for human health. Scientists are particularly eager to unravel the function of obulins and determine whether obelisks represent a significant component of our internal microbial landscape.
The discovery of obelisks serves as a powerful reminder of how much we still have to learn about the microscopic world surrounding and inhabiting us. It underscores the complexity of biological systems and the endless potential for groundbreaking scientific revelations.