After the US Supreme court's KSR case, the trends for obvious and non-obvious rulings in terms of the CAFC decisions significantly increased and decreased, respectively. In re Kubin case, the invention disclosed the isolation and sequences of a polynucleotide that encodes a Natural Killer Cell Activation Inducing Ligand (NAIL) polypeptide. The soluble NAIL polypeptides could serve as an adjuvant in combination with vaccines. However, the appellants employed conventional methods to isolate a cDNA encoding NAIL and determine the cDNA's full nucleotide sequence. Thus, the CAFC affirmed that a skilled artisan has a reasonable expectation of success in deriving the claimed invention in light of the teachings of the prior art. Based on this investigation, developers of human vaccines should contemplate the obvious barrier to patent prosecution. Furthermore, we also need to follow up the CAFC's decision on the patentability of the isolated DNA containing sequence. A CAFC dissenting opinion stressed that the difference between an isolated DNA sequence and the product occurring in nature is just in the isolated form. Such a patent would not be "markedly different characteristics from any found in nature."