This website uses cookies to ensure you get the best experience on our website. Learn more

Move Over, Double Helix: A New Form of DNA Has Just Been Discovered

This is the first time it's ever been seen in a living cell.

When we learn about human genetics in high school biology class, one of the most basic things we learn about is the DNA double helix, the twisting ladder-shaped structure that holds our genetic code. But scientists have long suspected there’s another type of DNA that looks quite different from the famous Watson-Crick model. They theorized that it’s knot-shaped, though they’d never observed it in a living cell … until now.

In a paper published Monday in the journal Nature Chemistry, a team of researchers describe their evidence for the existence and possible function of this knotty DNA, called “human telomeric i-motif.” To identify the i-motif DNA, the researchers, led by first author Mahdi Zeraati a Ph.D. student at the Garvan Institute of Medical Research in Sydney, Australia, developed an antibody that would bind to the elusive DNA and allow them to capture images of it with the help of immunofluorescent staining. They suspect that the i-shaped DNA, which had previously only been observed in lab conditions very different from those in a living cell, regulates some genetic functions.

Researchers observed the i-motif DNA blink in and out, suggesting that it's regulating a cell function.

Article continues below

Our Science and Innovation teams bring you all of today’s news that’s helping shape your tomorrow.
Sign up for our newsletter:

“We provide the first direct evidence for the presence of i-motif structures in the nuclei of human cells,” the study’s authors write, as this is the first time anyone has observed the i-motif DNA, except for in lab conditions that don’t represent actual conditions in a living cell. The fact that scientists finally observed this different form of DNA in human cells is a pretty big deal, but it’s actually even more than just a different shape. It seems to play by different rules than double-helix DNA, too. It employs nucleotides — the basic A, G, T, and C units that compose DNA — a lot differently than helical DNA does.

“The i-motif is a four-stranded ‘knot’ of DNA,” Marcel Dinger, Ph.D., an associate professor at Garvan and one of the study’s authors, explained in a statement released Monday. “In the knot structure, C letters on the same strand of DNA bind to each other — so this is very different from a double helix, where ‘letters’ on opposite strands recognize each other, and where Cs bind to Gs.”

This paper represents a very early stage of figuring out what the i-motif DNA actually does in human cells. One idea the team has is that the i-motif DNA regulates some cell function, as indicated by the fact that it seemed to blink on and off in their observations. “We think the coming and going of the i-motifs is a clue to what they do,” said Zeraati. “It seems likely that they are there to help switch genes on or off, and to affect whether a gene is actively read or not.”

Future studies of the i-motif DNA will be necessary to figure out exactly what its role is, but this paper sets the groundwork for observing it, which is a significant step toward unlocking its mysteries.

Elizabeth Holmes' 150 Black Turtlenecks, Explained by a Fashion Psychologist

"A 'work uniform' becomes the wearer's signature, their identity."

Throughout the rise and epic fall of Theranos CEO and high-profile scammer Elizabeth Holmes, her signature black turtleneck has taken center stage. Holmes has admitted to owning about 150 of them, calling them her “uniform.” In adopting this austere, techno-monk look, she brilliantly used fashion psychology to mold herself internally and externally, even when she wasn’t speaking a single (deep-voiced) word.

Which Came First, God or Society? Scientists Think They Have an Answer

“It’s not the main driver of social complexity as some theories had predicted."

Amid hundreds of origin stories for hundreds of world societies, religion offers a tidy explanation for why humans started working together. It tells us that people with a common belief in a supernatural being who encouraged humans to get along — either by punishing the immoral or rewarding the righteous — united strangers to build complex societies. This “pro-social religion hypothesis” feels logical, but the researchers behind a paper published Wednesday in Nature argue that complex human societies probably developed the other way around.

Tool Discovered in 15th-Century Shipwreck Makes the Guinness Book of Records

"You can only dream about finding such a rare and precious artifact."

The Warwick Manufacturing Group, an academic department at the University of Warwick, is usually concerned with the future. Its researchers use high-resolution lasers and 3D visualizations to create advanced materials for industries like automotive and aerospace. So, when they were called on by a shipwreck hunter curious to work with them on a rare new discovery, they were intrigued.

Colorado Study on Cannabis-Linked ER Visits Exposes Dangers of Weed Edibles

"I don't think it should be available for recreational purposes."

In an infamous 2014 editorial, New York Times columnist Maureen Dowd said she ate marijuana candy in Denver and felt like she died. Her hallucinations and paranoia lasted for a night, and she learned the next day she ate more than the recommended dose. While it was easy for the internet to laugh, what happened to Dowd is increasingly commonplace in Colorado and can be very dangerous, as doctors in Denver reported on Monday.

Geomagnetic Storms May Bring the Northern Lights to Some States on Saturday

This Saturday, some Americans may witness a dazzling light show.

Our planet is bookended by two cosmic displays that spread around the poles, the aurora borealis and the aurora australis. To see these natural displays of light, people must usually journey extremely far north or south, to places like Antarctica, Iceland, or Alaska. But sometimes geomagnetic storms temporarily disturb the Earth’s magnetosphere, giving people in less remote places a chance to see a dazzling light show. This Saturday could be one of those rare moments for some Americans.