In a thinly worded unanimous decision in Assn. for Molecular Pathology v. Myriad Genetics, Inc. on June 13, 2013, the U.S. Supreme Court held that patent claims directed to genes are not patent eligible despite being claimed in an isolated form. The Court indicated that in order to qualify for patentability, a composition must be not only non-naturally occurring, but also have markedly different characteristics from any found in nature. An isolated naturally occurring DNA gene sequence, or amplification fragment, though made useful to provide a diagnosis for disease propensity, is apparently not modified sufficiently through isolation from its chromosomal environment to meet the standard for patentability.

The Court distinguished the patent eligibility of cDNA molecules, which are copies of RNA molecules encoding for a protein, but having certain non-useful corresponding original DNA (introns) removed. The Court also distinguished the patent eligibility of novel DNA sequences that are not found in nature but are instead engineered. Therefore, despite the surprising nature of this decision, there remains numerous ways in which patent eligible DNA claims can be drafted and protected, such as by claiming cDNA or including the native DNA in association with other components.