In Association for Molecular Pathology v. Myriad Genetics, the Supreme Court held that Myriad’s isolated BRCA DNA patent claims were invalid because an isolated DNA with the same sequence as a natural DNA is a product of nature. The decision has two fundamental flaws. First, due to a faulty claim construction by the trial court, the Supreme Court was never informed that isolated DNA is a synthetic molecule that is not actually isolated from nature, or that isolated DNA lacks functional information encoded by chemical modifications present in natural human DNA. Second, the Court ignored a long line of cases indicating that an isolated products of nature is patent-eligible if it has a novel function not shared by the same compound in its natural state. Under this traditional test, isolated BRCA DNA should be patent eligible because is useful for diagnostic testing to identify mutations associated with breast and ovarian cancer, whereas native BRCA DNA is not.

Without explicitly overruling precedent, the Court applied a vague “markedly different” test to analyze Myriad’s isolated DNA claims. Under this test, cDNA is patent eligible even though it is synthesized by copying the natural sequence of mRNA in almost exactly the same way that isolated DNA is synthesized by copying the sequence of native DNA. A further complication is that cDNA is only patentable if its sequence is long enough to include a splice junction, which marks the site where part of the DNA sequence was removed by a natural process.

Considering the fine line drawn in Myriad, the “markedly different” test will be difficult for lower courts and the Patent Office to interpret in future cases. Thus, Myriad is likely to have limited impact on future developments in patent law unless the Supreme Court subsequently extends its ban on isolated DNA patenting to encompass other isolated natural products. Even within the field of DNA patenting, Myriad is unlikely to have substantial have long-term consequences because isolated DNA with a natural sequence is no longer novel or nonobvious, and is not even needed for diagnostic testing with current technology. Future innovation is genuinely threatened by overbroad patent claims on fundamental discoveries, but there are better mechanisms to weed out this pernicious threat than an unfocused products of nature exception.