The US Patent and Trademark Office has issued a patent fundamental to RNA silencing to a UK tech transfer firm. The new patent awarded to Plant Bioscience Limited (PBL) of Norwich for discoveries in plants made by David Baulcombe, University of Cambridge, and Andrew Hamilton, University of Glasgow, is likely to affect ongoing industrial research, gene therapeutic products and commercial silencing kits for many organisms including humans. This patent (US 8,097,710) is the third and broadest issued to date based on the initial invention (Nat. Biotechnol. 28, 300, 2010). Jan Chojecki, managing director of the part-publicly funded PBL, says companies have already come forward to purchase a license under the new terms, which covers the use of RNA strands of 20–24 base pairs in length. PBL will grant licenses to US-based industry but has a stated policy not to enforce rights in academia. The terms are flexible, he adds, so the patent should not block innovation. “We are here to see fair recognition of a public-sector innovation, and to ensure that resources come back into UK science,” says Chojecki. Scott Lloyd, a patent attorney and analyst at Nerac of Connecticut, points out that the use of 3-prime overhangs on RNA strands, which are already widely used to enable efficient silencing in human cells, is not described in the patent, so companies developing human therapeutics may have a defense against the need to license with PBL.