In an eagerly-awaited yet controversial decision, the US Supreme Court has unanimously ruled that naturally-occurring, non-modified sequences of DNA cannot be patented under US law.

In so doing, the Court rejected the longstanding practice of the United States Patent and Trademark Office (USTPO) of granting patents for isolated DNA sequences.

The Court did however hold that complementary, or cDNA, is patentable on the basis that it does not occur naturally and it is, through human intervention, a new creation.

The Court also left open the possibility of gene patents on method and application of knowledge claims, and claims concerning altered gene sequences.

The USTPO has acknowledged that the decision will mean significant changes to its patent examination policy and has issued preliminary guidance.

The ramifications of this ruling are likely to be felt beyond the US. It has the potential to affect a diverse range of industries, not least biotech (including in the fields of agricultural and environmental biotech), pharmaceuticals, healthcare and personalised medicine.

Association for Molecular Pathology v Myriad Genetics


Myriad Genetics Inc., held several patents relating to two genes, BRCA1 and BRCA2, mutations of which are involved in the development of certain cancers, primarily breast and ovarian cancer. Having discovered the precise location of these genes, Myriad was able to determine the genes’ typical nucleotide sequence and therefore develop diagnostic tests and screening procedures to assess an individual’s risk of developing these forms of cancer. Myriad’s patents covered these isolated genes, their synthetic coding equivalent cDNA (see below), and mutations of the same, as well as the methods to detect the sequences and mutations, and the afore-mentioned diagnostic tests and procedures. Myriad actively enforced its intellectual property rights.

In December 2009 the Association for Molecular Pathology (amongst others) filed a lawsuit in the US seeking to have Myriad’s patents declared invalid under 35 USC § 101, claiming that Myriad’s patents covered products of nature, prevented accessible cancer testing, and hindered scientific research and innovation. The District Court granted summary judgment in favour of plaintiffs, holding that Myriad’s composition claims were invalid as they covered products of nature. On appeal, the Federal Circuit judges, each for different reasons, affirmed in part and reversed in part the District Court’s decision in holding that “isolated” DNA, cDNA and the claimed screening methods were patentable. Only the claims relating to comparing and analyzing DNA sequences were considered ineligible for patenting.

However, the Supreme Court granted a writ of certiorari which vacated the Federal Circuit’s judgement and remanded the case in light of the Mayo v Prometheus decision. On remand, the Federal Court largely affirmed its original decision. In September 2012, the Supreme Court granted a second writ of certiorari and heard oral arguments on 15 April 2013. The judgment was published on 13 June 2013.

The Decision

Isolated DNA Sequences are Non-Patentable Products of Nature

The Supreme Court held that naturally-occurring DNA sequences are products of nature and do not become patentable merely because they have been isolated. The Court considered that Myriad did not create or alter the genetic structure of the DNA nor any of the genetic information encoded by the genes in question. Additionally, as the genes’ location and order of nucleotides already existed in nature, the Court felt that Myriad’s principal contribution was limited to finding the precise location of these (albeit “important and useful”) genes. The Court further commented that such a discovery, no matter how “groundbreaking, innovative, or even brilliant” was not enough on its own to satisfy 35 USC § 101. It therefore held that Myriad’s patents “fell squarely within the law of nature exception”, and were invalid.

However, the Court also held that as cDNA is not naturally-occurring, it may be patented.

All About Exons

DNA comprises regions of coding exons and non-coding introns. Through the natural processes of transcription and translation, the introns are removed, leaving only the coding exons. However, scientists are able create a synthetic form of this exon-only DNA, known as complementary or cDNA.

In its decision, the Court considered that although cDNA retains the naturally-occurring exons of the original DNA, without introns, it is a distinct non-naturally occurring molecule. Whilst acknowledging that the nucleotide sequence of cDNA may have been dictated by nature, the Court also stated that it is the intervention of a lab technician involved in the creation of the cDNA which “unquestionably creates something new”. Therefore the Court held that, bar certain limited exceptions, cDNA is not a product of nature and is therefore patent-eligible under 35 USC § 101. In a footnote however, the Court made it clear that it expressed no opinion as to whether cDNA would satisfy other statutory requirements of patentability.

Door left open for other claims

The Court was concerned to highlight exactly what was not covered by the decision:

  1. method claims - the Court emphasised that method claims were not the subject of the decision and that the option had been there for Myriad to seek a method patent in relation to the genes;  
  2. patents on new applications of knowledge – the Court stressed that applications of knowledge about the genes for which Myriad was in an “excellent position” to claim were not before the Court; and  
  3. claims on altered sequences - no opinion was expressed as to patentability of DNA sequences in which the sequence of naturally-occurring nucleotides has been altered.

By implication therefore, gene patents formulated as per the above claim types may still be patentable.

Impacts of the Decision

The impacts of the decision are such that the USTPO has issued a memorandum providing preliminary guidance to Patent Examining Corps. The memo states that the decision “significantly changes the Office’s examination policy regarding nucleic-acid related technology” and confirms that “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.” More comprehensive guidance is to be issued shortly.

There are concerns that through this ruling, the commercial incentives in genomic research could be lost and that existing gene patents may be revoked, both in the US and in other jurisdictions were they to follow suit. However, the impacts in the field of human genomic study may be limited given that many claims to such gene sequences have or will soon come off patent and that projects such as the Human Genome Project have, for the most part, made the human genome publicly available. The effect will perhaps be greater in those industries working on genetic modification technologies or with diagnostics and therapies, such as in personalised medicines. Similarly, the decision may have impacts for non-human gene patents used in, for example, animal healthcare and agricultural biotechnology sectors.

However, as noted above, the Court was careful to limit its decision to the precise issue before it and has not categorically ruled out patenting of products of nature, howsoever altered. The Court reaffirmed that “the rule against patents on naturally occurring things [contained in 35 USC § 101] has limits” and reiterated the warning in Mayo v Prometheus that “too broad an interpretation of this exclusionary principle could eviscerate patent law”. The affirmation that cDNA is patentable subject matter, at least to the extent of satisfying 35 USC § 101, should also provide some further comfort.

The Supreme Court’s decision is available here.

The USTPO Memorandum is available here.