Researchers mapped where DNA first opens and how a helicase gate may release one strand as genome copying begins.

Before a cell can divide, it must open its tightly wound DNA and begin copying the entire genome. Researchers at the MRC Laboratory of Medical Sciences (LMS) and collaborating institutions have now traced this process to one of its earliest moments, revealing where DNA first separates inside living cells and identifying a molecular gate that helps launch replication.

Published in Nature Communications, the findings provide a closer view of how cells begin duplicating their genetic material. Because copying errors can damage the genome, the start of DNA replication must be controlled with exceptional precision.