The Patent Act of 1952, codified in Title 35 of the United States Code, defines current patent law. According to section 101, one who "invents or discovers any new and useful process, machine, manufacture, or any composition of matter, or any new and useful improvement thereof, may obtain a patent therefore, subject to the conditions and requirements of this title." To be patentable, an invention must be useful, novel, and nonobvious. The requirement of usefulness, or utility, is satisfied if the invention is operable and provides a tangible benefit. To be judged novel, the invention must not be fully anticipated by a prior patent, publication, or other knowledge within the public domain. A nonobvious invention must not have been readily within the ordinary skills of a competent artisan at the time the invention was made. The invention must be fully described. Once the United States Patent and Trademark Office (USPTO) issues a patent, the owner enjoys the right to exclude others from making, using, selling, offering to sell, or importing into the United States the patented invention. Generally, the term of a patent is 20 years from the date the application was filed. In the process of obtaining a patent, the information associated with the patent is published and made available to the public. In a June 2013 decision, the Supreme Court of the United States ruled in Association for Molecular Pathology v. Myriad Genetics, Inc. , that genomic DNA was ineligible for patenting under 35 U.S.C. §101 because of the "product of nature" doctrine. Products of nature (preexisting substances found in the wild) may not be patented, per se . However, the courts have also determined that such a product of nature may be patentable if significant artificial changes are made. By purifying, isolating, or otherwise altering a naturally occurring product, an inventor may obtain a patent on the product in its altered form. Adopting the view that isolated and purified genomic DNA satisfied this exception to the "product of nature" doctrine, the USPTO issued over 50,000 patents relating at least in part to DNA. However, some experts believed that the decision to patent human genes misconstrued the "product of nature" principle. In their view, the fact that scientists have isolated a gene is a "technicality" that did not allow genes to be patented. The Supreme Court decision in Myriad reflects this latter position. The litigation commenced on May 12, 2009, when the Association for Molecular Pathology and 19 other plaintiffs, including individual physicians, patients, and researchers, filed a lawsuit against the USPTO, Myriad Genetics, Inc., and the Directors of the University of Utah Research Foundation. The plaintiffs challenged several patents owned by Myriad that claim isolated human genes known as BRCA1 and BRCA2. Certain alterations or mutations in these genes are associated with a predisposition to breast and ovarian cancers. Due to its intellectual property rights, Myriad was the sole commercial provider of genetic testing related to breast and ovarian cancer associated with the BRCA1 and BRCA2 genes. The plaintiffs asserted that Myriad's gene patent claims were invalid because, in their view, human genes are naturally occurring products that do not constitute patentable subject matter. The U.S. District Court for the Southern District of New York sided with the plaintiffs and held that Myriad's gene patent claims were invalid under 35 U.S.C. §101. Judge Sweet reasoned that Myriad's claimed isolated DNA was not "markedly different from native DNA as it exists in nature" and therefore could not be patented. Following an appeal, the Federal Circuit reversed this holding. The Court of Appeals reasoned that "isolated" DNA is not merely "purified" DNA—rather, it has been "manipulated chemically so as to produce a molecule that is markedly different from that which exists in the body." Under this reasoning, human genes consist of patentable subject matter. The Supreme Court subsequently agreed to hear the Myriad case but did not issue a ruling in the matter. Rather, on March 26, 2012, the Court vacated the judgment and remanded the matter back to the Federal Circuit with instructions to reconsider the appeal. The Federal Circuit responded by once again holding that both isolated DNA and cDNA were patent eligible. The Supreme Court then granted certiorari . Justice Thomas, writing for the Court, initially observed that Myriad had neither created nor altered the generic information encoded in the BRCA1 and BRCA2 genes. Rather, Myriad had discovered the precise location and genetic sequence of those genes. According to Justice Thomas, then, "Myriad did not create anything. To be sure, it found an important and useful gene, but separating that gene from its surrounding genetic material is not an act of invention." The Supreme Court also was unimpressed that Myriad claimed DNA that had been isolated from the human genome through the severing of chemical bonds, with a non-naturally occurring molecule as a result. According to Justice Thomas, "Myriad's claims are simply not expressed in terms of chemical composition, nor do they rely in any way on the chemical changes that result from the isolation of a particular section of DNA." The Court took a more favorable view of cDNA, however. Observing that "cDNA retains the naturally occurring exons of DNA, but it is distinct from the DNA from which it was derived," Justice Thomas concluded that cDNA did not constitute a "product of nature" and therefore could be patented. Justice Thomas also found it important to note what the Myriad opinion did not implicate. The case involved neither an innovative method of manipulating genes while searching for the BRCA1 and BRCA2 genes, the Court explained, nor new applications of knowledge about those genes. The Court also indicated that it had not considered the patentability of DNA in which the order of the naturally occurring nucleotides has been altered. Instead, the Court "merely [held] that genes and the information they encode are not patent eligible under §101 simply because they have been isolated from the surrounding genetic material." The opinion of Justice Thomas was joined in full by seven of his colleagues. Justice Scalia contributed a one-paragraph concurring opinion that joined the judgment of the Court and all of its opinion except those portions "going into fine details of molecular biology." Justice Scalia found himself "unable to affirm those details on my own knowledge or even my own belief." This shortcoming did not prevent him from concluding that isolated genomic DNA was identical to its natural state, however, while cDNA could be patented because it was a synthetic creation not found in nature. Shortly after the Supreme Court issued its ruling, Myriad Genetics, Inc. and other plaintiffs commenced patent infringement litigation against certain genetic testing service providers. Although the Supreme Court invalidated Myriad's claims on genomic DNA, Myriad asserted claims toward other genetic technologies. These claims recite in part, among other subject matter, a "method for detecting a germline alteration in a BRCA1 gene," an "isolated DNA coding for a BRCA1 polypeptide," a "method for screening germline of a human subject for an alteration of a BRCA1 gene," and a "pair of single-stranded DNA primers." This litigation may provide further guidance as to the patentability of gene-related inventions in the wake of the Supreme Court's decision. The Myriad holding is expected to make it difficult for inventors to protect early, gene-related discoveries through the patent system. In particular, how the courts will apply the decision to other biologic products, including antisense DNA, microRNA, nucleic acids, proteins, and stem cells remains to be seen. However, the Supreme Court appears to approve of patent claims drawn to chemical modifications of naturally occurring substances, particularly if that modification endows the substance with a new property. For example, even slightly altered genes would appear to comprise patentable subject matter. As the USPTO explained in a memorandum released hours after the Myriad case issued: As of today, naturally occurring nucleic acids are not patent eligible merely because they have been isolated. Examiners should now reject product claims drawn solely to naturally occurring nucleic acids or fragments thereof, whether isolated or not, as being ineligible subject matter under 35 U.S.C. §101. Claims clearly limited to non-naturally-occurring nucleic acids, such as a cDNA or a nucleic acid in which the order of the naturally occurring nucleotides has been altered (e.g., a man-made variant sequence), remain eligible. Other claims, including method claims, that involve naturally occurring nucleic acids may give rise to eligibility issues and should be examined under the existing guidance ... Firms that employ cDNA to develop novel therapeutic proteins stand to benefit from the Myriad case. Still, one wonders if the Court neglected to recall its earlier holding in Mayo v. Prometheus that that conventional or obvious pre-solution activity does not transform an unpatentable law of nature into a patent-eligible application of such law. cDNA is derived from DNA and is identical to DNA except that the non-coding regions have been removed—a choice dictated by natural laws and not the inventor. Further, the production of cDNA is reportedly well-understood and routine. Arguably, then, no scientific distinction pertinent to patent eligibility exists between genomic DNA and cDNA. Under Myriad , however, DNA is not patentable subject matter but cDNA may be patented. Gene patents have been subject to a longstanding debate. Although the Supreme Court declared that genomic DNA may not be patented, it held that cDNA fulfills the requirements of 35 U.S.C. §101. In addition, the USPTO has issued other sorts of gene-related inventions, including those relating to genetic screening methods, polypeptides, DNA primers, and other technologies. As a result, the debate on gene patents potentially remains active. Some of its main contours are outlined below.