MPEP 2131.02
Genus-Species Situations

Ninth Edition of the MPEP, Revision 07.2022, Last Revised in February 2023

Previous: §2131.01 | Next: §2131.03

2131.02    Genus-Species Situations [R-07.2022]


"A generic claim cannot be allowed to an applicant if the prior art discloses a species falling within the claimed genus." The species in that case will anticipate the genus. In re Slayter, 276 F.2d 408, 411, 125 USPQ 345, 347 (CCPA 1960); In re Gosteli, 872 F.2d 1008, 10 USPQ2d 1614 (Fed. Cir. 1989) (Gosteli claimed a genus of 21 specific chemical species of bicyclic thia-aza compounds in Markush claims. The prior art reference applied against the claims disclosed two of the chemical species. The parties agreed that the prior art species would anticipate the claims unless applicant was entitled to his foreign priority date.).


A genus does not always anticipate a claim to a species within the genus. However, when the species is clearly named, the species claim is anticipated no matter how many other species are additionally named. See Ex parte A, 17 USPQ2d 1716 (Bd. Pat. App. & Inter. 1990) (The claimed compound was named in a reference which also disclosed 45 other compounds. The Board held that the comprehensiveness of the listing did not negate the fact that the compound claimed was specifically taught. The Board compared the facts to the situation in which the compound was found in the Merck Index, saying that "the tenth edition of the Merck Index lists ten thousand compounds. In our view, each and every one of those compounds is ‘described’ as that term is used in [pre-AIA] 35 U.S.C. 102(a), in that publication."). Id. at 1718. See also In re Sivaramakrishnan, 673 F.2d 1383, 213 USPQ 441 (CCPA 1982) (The claims were directed to polycarbonate containing cadmium laurate as an additive. The court upheld the Board’s finding that a reference specifically naming cadmium laurate as an additive amongst a list of many suitable salts in polycarbonate resin anticipated the claims. The applicant had argued that cadmium laurate was only disclosed as representative of the salts and was expected to have the same properties as the other salts listed while, as shown in the application, cadmium laurate had unexpected properties. The court held that it did not matter that the salt was not disclosed as being preferred, the reference still anticipated the claims and because the claim was anticipated, the unexpected properties were immaterial.).


"[W]hether a generic disclosure necessarily anticipates everything within the genus … depends on the factual aspects of the specific disclosure and the particular products at issue." Sanofi-Synthelabo v. Apotex, Inc., 550 F.3d 1075, 1083, 89 USPQ2d 1370, 1375 (Fed. Cir. 2008). See also Osram Sylvania Inc. v. American Induction Tech. Inc., 701 F.3d 698, 706, 105 USPQ2d 1368, 1374 (Fed. Cir. 2012) ("how one of ordinary skill in the art would understand the relative size of a genus or species in a particular technology is of critical importance").

A reference disclosure can anticipate a claim when the reference describes the limitations but "'d[oes] not expressly spell out' the limitations as arranged or combined as in the claim, if a person of skill in the art, reading the reference, would ‘at once envisage’ the claimed arrangement or combination." Kennametal, Inc. v. Ingersoll Cutting Tool Co., 780 F.3d 1376, 1381, 114 USPQ2d 1250, 1254 (Fed. Cir. 2015) (quoting In re Petering, 301 F.2d 676, 681(CCPA 1962)). In Kennametal, the challenged claim was to a cutting tool requiring a ruthenium binding agent with a physical vapor deposition (PVD) coating. The reference described all the elements of the claimed coated cutting tool but did not explicitly disclose the specific combination of ruthenium binding agent with a PVD coating. However, the reference disclosed that ruthenium was one of five specified binding agents and PVD was one of three suitable coating techniques. The Federal Circuit stated that the reference’s "express ‘contemplat[ion]’ of PVD coatings provided sufficient evidence that a reasonable mind could find that a person of skill in the art… would immediately envisage applying a PVD coating. Thus, substantial evidence supports the Board's conclusion that [the reference] effectively teaches 15 combinations, of which one anticipates pending claim 1. Though it is true that there is no evidence in [the reference] of ‘actual performance’ of combining the ruthenium binder and PVD coatings, this is not required." Kennametal, 780 F.3d at 1383, 114 USPQ2d at 1255 (citations omitted). See also Nidec Motor Corp. v. Zhongshan Broad Ocean Motor Co., 851 F.3d 1270, 1274, 122 USPQ2d 1116, 1120 (Fed. Cir. 2017) ("Kennametal does not stand for the proposition that a reference missing a limitation can anticipate a claim if a skilled artisan viewing the reference would "at once envisage" the missing limitation. Rather, Kennametal addresses whether the disclosure of a limited number of combination possibilities discloses one of the possible combinations.").

When a claimed compound is not specifically named in a reference, but instead it is necessary to select portions of teachings within the reference and combine them, e.g., select various substituents from a list of alternatives given for placement at specific sites on a generic chemical formula to arrive at a specific composition, anticipation can only be found if the classes of substituents are sufficiently limited or well delineated. Ex parte A, 17 USPQ2d 1716 (Bd. Pat. App. & Inter. 1990). If one of ordinary skill in the art is able to "at once envisage" the specific compound within the generic chemical formula, the compound is anticipated. One of ordinary skill in the art must be able to draw the structural formula or write the name of each of the compounds included in the generic formula before any of the compounds can be "at once envisaged." One may look to the preferred embodiments to determine which compounds can be anticipated. In re Petering, 301 F.2d 676, 133 USPQ 275 (CCPA 1962).

In In re Petering, the prior art disclosed a generic chemical formula "wherein X, Y, Z, P, and R'- represent either hydrogen or alkyl radicals, R a side chain containing an OH group." The court held that this formula, without more, could not anticipate a claim to 7-methyl-9-[d, l'-ribityl]-isoalloxazine because the generic formula encompassed a vast number and perhaps even an infinite number of compounds. However, the reference also disclosed preferred substituents for X, Y, Z, P, R, and R' as follows: where X, P, and R' are hydrogen, where Y and Z may be hydrogen or methyl, and where R is one of eight specific isoalloxazines. The court determined that this more limited generic class consisted of about 20 compounds. The limited number of compounds covered by the preferred formula in combination with the fact that the number of substituents was low at each site, the ring positions were limited, and there was a large unchanging structural nucleus, resulted in a finding that the reference sufficiently described "each of the various permutations here involved as fully as if he had drawn each structural formula or had written each name." The claimed compound was 1 of these 20 compounds. Therefore, the reference "described" the claimed compound and the reference anticipated the claims.

In In re Schauman, 572 F.2d 312, 197 USPQ 5 (CCPA 1978), claims to a specific compound were anticipated because the prior art taught a generic formula embracing a limited number of compounds closely related to each other in structure and the properties possessed by the compound class of the prior art was that disclosed for the claimed compound. The broad generic formula seemed to describe an infinite number of compounds but claim 1 was limited to a structure with only one variable substituent R. This substituent was limited to low alkyl radicals. One of ordinary skill in the art would at once envisage the subject matter within claim 1 of the reference.

Compare In re Meyer, 599 F.2d 1026, 202 USPQ 175 (CCPA 1979) (A reference disclosing "alkaline chlorine or bromine solution" embraces a large number of species and cannot be said to anticipate claims to "alkali metal hypochlorite."); Akzo N.V. v. International Trade Comm’n, 808 F.2d 1471, 1 USPQ2d 1241 (Fed. Cir. 1986) (Claims to a process for making aramid fibers using a 98% solution of sulfuric acid were not anticipated by a reference which disclosed using sulfuric acid solution but which did not disclose using a 98% concentrated sulfuric acid solution.). See MPEP § 2144.08 for a discussion of obviousness in genus-species situations.