In its eagerly-awaited decision in Association for Molecular Pathology v. Myriad Genetics, Inc., the US Supreme Court has found that claims directed to isolated DNA sequences are not patent eligible, whereas claims directed to cDNA sequences may be patentable.

In a unanimous decision, the court decided that naturally occurring DNA segments are products of nature and that isolation of a particular DNA segment by breaking the covalent bonds holding the sequence in place cannot render the sequence patent eligible.   

This means that claims directed to an isolated DNA sequence are no longer patentable in the US, and the US Patent and Trademark Office has already issued a guidance note confirming this change in policy with immediate effect. 

However, cDNA sequences (in which the non-coding introns have been removed) may be patent eligible as they are not naturally-occurring.  Thus, the exclusion from patentability does not apply to synthetic cDNA sequences provided their sequence is distinct from the DNA from which they were derived.  However, short strands of DNA may not contain any intronic sequences for removal when creating cDNA meaning that short strands of cDNA may not be patent eligible if their sequence is indistinguishable from natural DNA.

It is important to note that the decision is confined to DNA sequences only and the court has not considered the patentability of new applications based on the knowledge of a DNA sequence or the patentability of DNA sequences in which the order of the naturally occurring nucleotides has been altered, both of which may still be considered patent eligible. 

In summary, it will no longer be possible to obtain patents for isolated DNA sequences in the US and the decision is likely to result in the invalidation of many existing patents claiming naturally occurring DNA segments.  Although the decision is very specific to DNA sequences, it also raises the question of whether other isolated natural products may now be considered patent ineligible in the US by the same logic.