Continuing a trend of narrowing the scope of patentable subject matter, the US Supreme Court's recent Myriad decision held that naturally occurring "isolated DNA" sequences are not patentable subject matter. However, the Court found that cDNA is still patentable and did not address the patentability of method claims involving isolated DNA sequences. In view of this important decision, biotechnology companies and other life sciences organizations should carefully audit their DNA and gene-based patent portfolios and consider new claim drafting strategies to provide maximum protection for new inventions in these areas.

The Court Distinguishes Between "Isolated DNA" and cDNA

On June 13, 2013, the Supreme Court issued its decision in Association for Molecular Pathology v. Myriad Genetics Inc., et al., and held that an "isolated DNA sequence" is not patentable subject matter because it is a naturally occurring product of nature. Myriad had a number of patents that claimed the entire genetic sequence of BRCA1 and BRCA2, two genes on human chromosomes 17 and 13, respectively, whose mutations have been shown to increase the risk of breast cancer in women from 50-80%. Myriad had claims that covered the entire DNA sequence of these genes and segments thereof, effectively allowing Myriad a monopoly over any use, synthesis and detection methods that involved these two genes. While the Supreme Court recognized that "Myriad found the location of the BRCA1 and BRCA2 genes," it concluded that "discovery, by itself, does not render the BRCA genes 'new . . . composition[s] of matter,' §101, that are patent eligible."

The Court, however, differentiated between DNA sequences that can be found in nature and ones that cannot. DNA that can be found in nature, e.g., a genomic DNA sequence, is not patentable subject matter. In contrast, a cDNA fragment, which lacks non-coding intron sequences, is patentable subject matter as it does not exist in nature. Such cDNA only comes into existence when synthesized in a laboratory, using messenger RNA, or mRNA, as a template. In contrast to genomic DNA, mRNA contains only the nucleotides corresponding to the exons (or amino acid coding segments) of the original DNA strand. Under the Court's reasoning, isolated mRNA itself would be unpatentable because it is exists naturally in the human body. But cDNA, which is created from the mRNA templates, would be patentable because it is not naturally occurring. In sum, if a sequence search demonstrates that a particular DNA sequences matches genomic DNA of any species, the sequence itself is unpatentable naturally occurring DNA when in a native context, even if the DNA sequence was actually synthesized in a laboratory.

What Remains Patentable?

While isolated DNA is no longer patentable, cDNA or fragments thereof remain patentable subject matter as long as the cDNA includes sequences of neighboring introns with the exons removed such that it is not found in nature. The Court also emphasized that the Myriad decision does not address patentability of DNA in which the order of the naturally occurring nucleotides has been altered. Therefore, patent protection may still be obtained for any newly created, altered, or recombined DNA sequence that does not appear as such in nature, as long as all other requirements of patentability are satisfied. Combining naturally occurring DNA sequences with other sequences, e.g., combining a genomic DNA sequence with a heterologous promoter, should therefore be deemed to create patentable subject matter. Accordingly, the Court's decision does not appear to affect patentability of recombinant constructs, transgenic organisms, chemically modified DNA and the like.

Impact on Diagnostic Methods

It is important to note that the Supreme Court decision did not involve method claims. ("Had Myriad created an innovative method of manipulating genes while searching for the BRCA1 and BRCA2 genes, it could possibly have sought a method patent."). Similarly, the court found that new applications involving the discovery of DNA sequences were not impacted by this decision. ("[T]his case does not involve patents on new applications of knowledge about the BRCA1 and BRCA2 genes.").

While the Supreme Court did not lay out the contours of what types of methods based on naturally occurring DNA sequences might be patentable, the decision nevertheless may impact patentability of genetic-testing inventions in which a naturally occurring mutation is correlated with a disease. The correlation between a mutation and a phenotype may be considered a law of nature just as a correlation between naturally-produced metabolites and therapeutic efficacy and toxicity was in a 2012 Supreme Court Decision. See Mayo v. Prometheus, 132 S. Ct. 1289 (2012). However, diagnostic methods that involve using synthesized mRNA tags, cDNA, or radio labeled DNA or RNA probes to detect for naturally occurring mutations likely remain patentable subject matter.


In order to obtain patent protection for diagnostic inventions, patent applications will need to be crafted precisely, navigating around the legal test and limitations established by the Federal Circuit and the Supreme Court. The danger is that such claims, if not drafted carefully, may not fully protect investments, as it may be possible to either design around the claimed invention or not obtain patent protection at all. Companies with genetic and DNA based inventions should seek counsel and audit their patent portfolios to determine which claims are likely be invalid as claiming naturally occurring DNA sequences. New claim drafting strategies should be employed and companies in litigation or contemplating litigation will need to reevaluate which claims can withstand a patentability challenge. Companies defending against DNA patents should also carefully evaluate whether they now have a viable summary judgment argument under 35 U.S.C. §101 to invalidate patents that fall within the Supreme Court's holding. Finally, companies that have taken licenses to DNA patents may also have an opportunity to renegotiate or challenge their existing licenses if the licensed claims are deemed unpatentable under this decision.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.