Id. The Board held it is not necessary to describe the exact details for preparing every species within the genus in order to claim the genus. Id. (citing Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988)). Thus, Noelle argues, the disclosure in his previous '799 application of the mouse form of CD40CR antibody was sufficient to support his later genus claims.

In support of this argument, UC cites the disclosure of a species (the rat insulin-encoding cDNA) within the scope of those generic claims. UC argues, citing In re Angstadt, 537 F.2d 498, 190 USPQ 214 (CCPA 1976) and Utter v. Hiraga, 845 F.2d 993, 6 USPQ2d 1709 (Fed. Cir. 1988), that because the '525 specification meets the requirements of Section(s) 112, Para(s) 1, for a species within both of these genera, the specification necessarily also describes these genera. Lilly responds that the district court did not clearly err in finding that cDNA encoding mammalian and vertebrate insulin were not adequately described in the '525 patent, because description of one species of a genus is not necessarily a description of the genus.

Id. at 503, 3 USPQ2d at 1335-36 (quoting Burson v. Carmichael, 731 F.2d 849, 852, 221 USPQ 664, 666 (Fed. Cir. 1984)). Kubota also cites Utter v. Hiraga, 845 F.2d 993, 6 USPQ2d 1709 (Fed. Cir. 1988), another case decided under the old rules, in which we stated: A party who, like Hiraga, relies on an earlier-filed application under 35 U.S.C. § 119 or 120 has the burden to show that the foreign or parent application supports later-added claims under 35 U.S.C. § 112 ¶ 1, regardless of whether that party is the junior or senior party in an interference.

Revel bears the burden of proving entitlement to the benefit of his earlier-filed Israeli application date. Utter v. Hiraga, 845 F.2d 993, 998, 6 USPQ2d 1709, 1713 (Fed. Cir. 1988). To meet this burden, Revel must prove that his application meets the requirements of 35 U.S.C. § 112, first paragraph, Bigham v. Godtfredsen, 857 F.2d 1415, 1417, 8 USPQ2d 1266, 1268 (Fed. Cir. 1988) (citing Cross v. Iizuka, 753 F.2d 1040, 1043, 224 USPQ 739, 741 (Fed. Cir. 1985)), which provides in pertinent part:

Our cases also provide that compliance with the "written description" requirement of § 112 is a question of fact, to be reviewed under the clearly erroneous standard. Gosteli, 872 F.2d at 1012, 10 USPQ2d at 1618; Utter v. Hiraga, 845 F.2d 993, 998, 6 USPQ2d 1709, 1714 (Fed. Cir. 1988). See, Chester v. Miller, 906 F.2d 1574, 15 USPQ2d 1333 (Fed. Cir. 1990) (parent application's disclosure of chemical species constituted 102(b) prior art against continuation-in-part (c-i-p) application on appeal, but did not provide sufficient written description to support c-i-p's claims to encompassing genus); In re Gosteli, 872 F.2d 1008, 10 USPQ2d 1614 (Fed. Cir. 1989) (foreign priority application's disclosure of chemical subgenus was insufficient written description to support genus claims of corresponding U.S. application); In re Wright, 866 F.2d 422, 9 USPQ2d 1649 (Fed. Cir. 1989) (application in "clear compliance" with § 112 "written description" requirement with respect to claim limitation that microcapsules were "not permanently fixed"); Utter v. Hiraga, 845 F.2d 993, 998, 6 USPQ2d 1709, 1714 (Fed. Cir. 1988) (holding generic interference count to scroll compressor supported by written description of foreign priority application, the court stated, "A specification may, wit

There may be merit to an argument from Unicorn's hearing demonstratives that “[a] specification may . . . contain a written description of a broadly claimed invention without describing all species that claim encompasses.” Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988). But the argument is untimely.

The Federal Circuit has not explained how the burden of proof should be allocated when a priority question arises in the context of an invalidity dispute. In a decision addressing the burden of proof in interference proceedings under the "old" interference rules, the court held in Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988) that "[a] party who, like Hiraga, relies on an earlier-filed application under 35 U.S.C. § 119 or § 120 has the burden to show that the foreign or parent application supports later added claims under 35 U.S.C. § 112, ¶ 1, regardless of whether that party is the junior or senior party in the interference." More recent decisions decided under the "new" interference rules make clear that after an interference has been declared, the party attacking the declaration must overcome the presumption that the decision is correct by disproving the priority ruling by a preponderance of the evidence.

" Atmel Corp. v. Info. Storage Devices, Inc., 198 F.3d 1374, 1381-82 (Fed. Cir. 1999). Whether a priority document contains sufficient disclosure under § 112, ¶ 1 is a question of law that we review de novo. Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988). However, "compliance with the written description aspect of that requirement is a question of fact" that we review for substantial evidence.

First, whether a claim is supported by an adequate written description is a factual inquiry, and has been for some time. Ariad, 598 F.3d at 1355; Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988). Hynix's argument that the ultimate determination of written description is a legal issue (relying on the Supreme Court's determination in KSR, 550 U.S. at 427, 127 S.Ct. 1727, that obviousness is a legal issue) is unavailing; written description and obviousness are distinct legal doctrines.

Blocking conditions conceivably occur often where a pioneering patent claims a genus and an improvement patent later claims a species of that genus. See, e.g., Utter v. Hiraga, 845 F.2d 993, 998 (Fed. Cir. 1988) (holding that in an interference proceeding "[t]here is no inconsistency in awarding a generic count to one inventor, while awarding a patentably distinct species count to another."); W.L. Gore Assocs., Inc. v. Garlock, Inc., 721 F.2d 1540, 1554 (Fed. Cir. 1983) ("Assuming [the first-in-time patent is] a dominating patent, the rule of law is clear that an accused infringer's employment of the process of a dominating patent does not render that employment an anticipation of an invention described and claimed in an improvement patent."). These blocking patents often serve the market well by pressuring both inventors to license their innovations to each other and beyond.