Scientists uncover a new role for DNA loops in repairing genetic damage

When DNA breaks, cells must repair it accurately to prevent harmful mutations. Researchers have discovered that during a key repair process called homologous recombination, the cell uses loops in its DNA structure to speed up the search for an intact copy of the damaged region. These loops act like shortcuts, allowing the repair machinery to scan along the chromosome in a directed way rather than randomly. This finding, published today in Science, reveals an unexpected function for chromatin loops—not just in organizing the genome, but also in helping maintain its integrity.

“Homologous recombination is a key DNA repair process often linked to cancer, but how it actually works within the 3D structure of the genome has been a big mystery," said Taekjip Ha, PhD, Director of the Program in Cellular and Molecular Medicine at Boston Children's Hospital and lead author of the study. "Our next step is to see if what we’ve found applies more broadly—for instance, does the same kind of homology search happen in other organisms like bacteria?”