On March 29, 2010, the Southern District of New York ruled that DNA isolated from human genes was not patentable. That controversial ruling was appealed to the Federal Circuit, and in November and December of 2010 attracted no fewer than ten amicus briefs arguing for its reversal. The Federal Circuit’s eventual decision in the appeal likely will have significant implications for the biotechnology and pharmaceutical industries, which are increasingly relying on DNA technology to develop new drugs and therapies. This article discusses the issues raised in the amicus briefs concerning the patentability of DNA, which in turn may shed light on how the Federal Circuit ultimately will decide the appeal.