An analysis of the evolution of the written description requirement vis-à-vis DNA and biotechnological inventions.

The Federal Circuit uses particular patent doctrines as policy levers to control the nature of the nation's patent output. Most recently, the court has looked to the narrow implementation of the written description doctrine to limit the scope of biotechnology patents in general and DNA patents in particular. Recent case-law now indicates a slow evolution within the Federal Circuit to loosen this control and broaden the scope of DNA patents.