Association for Molecular Pathology v. Myriad Genetics, Inc.
Association for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013), was a Supreme Court case, which decided that "a naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated." However, the Court allowed patenting of complementary DNA, which contains exactly the same protein-coding base pair sequence as the natural DNA, albeit with introns removed.
Source: Wikipedia — Association for Molecular Pathology v. Myriad Genetics, Inc. (CC BY-SA 4.0)