Quadruple Helix DNA Discovered In Human Cells

AFTER MORE THAN 100 years of looking, scientists have finally tracked down a strange, four-stranded form of DNA.

Our genetic code is usually incorporated in two strands of genetic material that wrap around one another, forming the famous ‘double helix’ structure. The discovery shows some of our genes are actually incorporated in a ‘quadruple helix‘.

These quadruplexes have been spotted in microorganisms before, but it’s the first time they’ve been seen in humans. It’s thought they may be involved in the development of some cancers, providing new avenues of research into treatments.

Professor Shankar Balasubramanian at the University of Cambridge, lead author of the study published in the journal Nature Chemistry, describes the quadruplexes as ‘exotic knots’. Regions of DNA rich in the compound guanine, one of the four chemicals that makes up the genetic code, are particularly prone to forming the four-stranded DNA.

Balasubramanian and his team conducted a computerised survey to search for guanine-rich sequences. They found them all over the human genome.

Four-strand DNA structure found in cells

Research is already under way into how to use synthetic molecules to trap and contain quadruplexes – stopping cells dividing and therefore preventing cancer. “The research indicates that quadruplexes are more likely to occur in genes of cells that are rapidly dividing, such as cancer cells,” says Balasubramanian. “For us, it strongly supports the idea of investigating the use of these four-stranded structures as targets for personalized treatments.” By ZOE CORMIER