DNA can recognise matching DNA without proteins

What is it about?

Scientists at Imperial College London, in collaboration with Cambridge, Oxford, Sorbonne, and Harvard University researchers, have uncovered compelling evidence that double-stranded DNA molecules can physically recognize matching DNA sequences without the help of proteins, shedding new light on one of biology's most fundamental, yet mysterious, processes – a first stage of genetic recombination. The findings show clear evidence that double stranded DNA molecules carrying identical genetic information tend to spend more time close together than unrelated DNA sequences. This phenomenon is suggested to proceed through a subtle, sequence-dependent physical interaction. https://www.imperial.ac.uk/news/articles/natural-sciences/chemistry/2026/dna-can-recognise-matching-dna-without-proteins/

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Why is it important?

This discovery could help explain the earliest stages of homologous recombination – a critical biological process that allows cells to repair damaged DNA, maintain genetic stability, and promote the genetic development beyond mutations. Every day, the DNA inside our cells experiences damage. To repair this damage accurately, cells often rely on homologous recombination, a process in which a damaged DNA locates another, undamaged, DNA molecule carrying the overall same genetic sequence and uses it as a template for repair. Recombination also occurs during the formation of sperm and egg cells, when DNA from the mother and father is mixed and reshuffled to create the genetic blueprint passed on to children. For this process to work correctly, matching genes – carrying instructions for the same biological functions – must recognize and exchange with one another accurately, like “eye for an eye” or “kidney for kidney.” Mistakes in this exchange can cause serious genetic disorders, cell damage, or processes linked to aging. While scientists understand many of the molecular steps involved in recombination, a longstanding question has remained unresolved: how do two matching DNA molecules recognise each other in the first place? Traditional explanations have focused on proteins, the cell’s factory workers, that actively bring homologous (almost identical) genes together. However, for decades some researchers have proposed a more intriguing possibility that DNA itself might possess an inherent ability to recognise matching sequences through purely physical interactions, even in the absence of proteins. Until now, experimental evidence for such a mechanism has been limited.

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