What is the significance of the genus-species relationship in patent claims?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The genus-species relationship is crucial in patent claims, particularly when considering changes to the scope of claims. According to MPEP 2163.05, “[t]he written description requirement for a claimed genus may be satisfied through sufficient description of a representative number of species.”

The MPEP provides guidance on this relationship:

• A claim to a genus may not be supported by the original disclosure if it only describes a single species.
• However, a single species can support a genus claim if the specification discloses “a representative number of species” or “structural features common to the members of the genus.”
• The disclosure must allow one skilled in the art to “visualize or recognize” the members of the genus.

For example, in Regents of the University of California v. Eli Lilly & Co., the court held that a generic claim to vertebrate or mammalian insulin cDNA was not supported by a disclosure of rat insulin cDNA. This case illustrates the importance of providing sufficient support for genus claims in the original disclosure.