Isolated DNA is not eligible for patenting, but synthetically created cDNA remains eligible.

Credit: Rana Royalty free/Alamy

The lowdown: A long-running case between genetic testing company Myriad Genetics and opponents of “gene patenting” has come to an end. The dispute focused on three patents owned by Myriad relating to two human genes, breast cancer type 1 susceptibility (BRCA1) and BRCA2, and protecting diagnostic tests that determine an individual's susceptibility to breast and ovarian cancer. Several plaintiffs, including the Association for Molecular Pathology, the American Civil Liberties Union and patient groups, alleged that these patents were invalid because they claim products of nature.

In the decision issued by the US's highest court last month, judges ruled that “a naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated” (see go.nature.com/ggAGlq for the full decision). Although the plaintiffs argued that cDNA should not be eligible for patent protection either because the nucleotide sequence of cDNA is dictated by nature (that is, by the mRNA template), the Court upheld the viability of cDNA patents. Scientists “unquestionably create something new when cDNA is made ... [that is] distinct from the DNA from which it was derived,” wrote the judges.

Both sides asserted their victory. Myriad said it still has strong patent protection for its BRCA tests, whereas the Association for Molecular Pathology said the ruling was the “right decision for the future of medicine and science ... and most importantly patients”.

The decision departs from the long-standing practice of the US Patent and Trademark Office, which previously permitted the patenting of isolated DNA. It also puts the United States at odds with jurisdictions such as Europe and Australia, where isolated genes remain patent eligible. Because the number of patents granted with claims to a simple isolated DNA peaked in the late 1990s, and many of these patents are due to expire soon, the decision is unlikely to impact a large number of patents. Moreover, many diagnostic patents rely on method claims, which were not under scrutiny in the current case.