  United States Court of Appeals
      for the Federal Circuit
                ______________________

            BAYER CROPSCIENCE AG,
                Plaintiff-Appellant,

                           v.

            DOW AGROSCIENCES LLC,
                Defendant-Appellee.
              ______________________

                      2013-1002
                ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 10-CV-1045, Judge Renee
Marie Bumb.
                ______________________

              Decided: September 3, 2013
                ______________________

   ROBERT J. KOCH, Milbank, Tweed, Hadley & McCloy,
LLP, of Washington, DC, argued for plaintiff-appellant.
With him on the brief were FREDRICK M. ZULLOW and
CHRISTOPHER J. GASPAR, of New York, New York.

    MARK S. DAVIS, Orrick, Herrington & Sutcliffe, LLP,
of Washington, DC, argued for defendant-appellee. With
him on the brief were RACHEL M. MCKENZIE; ELIZABETH
A. HOWARD, of Menlo Park, California; PETER A. BICKS
and ALEX V. CHACHKES, of New York, New York.
                ______________________

    Before PROST, BRYSON, and TARANTO, Circuit Judges.
2           BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

TARANTO, Circuit Judge.
    When the inventors applied for the patent at issue,
they had sequenced one gene coding for one enzyme, using
a test purportedly capable of finding other, similar genes.
In writing its claims, the owner—now Bayer CropScience
AG—decided to claim a broad category based on the
function of the particular enzyme, defining the category
by using a term with an established scientific meaning.
In doing so, Bayer got ahead of the science: experiments
had not confirmed that the term even applied to the
particular enzyme whose gene Bayer’s inventors had
sequenced. Soon science showed that it did not, and
Bayer knew as much years before its patent issued—but
did not change its claim language. When it ultimately
sued Dow AgroSciences for infringement, Bayer recog-
nized that the term used, in its established scientific
meaning, did not cover the accused product (itself differ-
ent from the particular enzyme whose gene Bayer’s inven-
tors had sequenced), so it argued for a broad functional
claim construction.
    Applying our decisions about the potentially unwel-
come consequences of a patentee’s chosen claim language,
the district court rejected Bayer’s argument, explaining
particularly the great breadth of the asserted functional
construction, and entered summary judgment of non-
infringement. We too are unpersuaded by Bayer’s pro-
posed claim construction. Because Bayer has presented
no argument for reversing the non-infringement judgment
independent of our adopting that construction, we affirm.
                      BACKGROUND
                            A
    The patent at issue concerns genetically modifying
plants in order to confer resistance to a commonly used
herbicide called 2,4-dichlorophenoxyacetic acid, or “2,4-D”
for short. The process works by inserting a particular
DNA segment—a segment containing the sequence of
nucleotides identified as the gene coding for a particular
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC               3

enzyme—into plant cells, which then reproduce to create
new cells that contain that gene. The plant cells produce
the enzyme that then catalyzes a biochemical reaction
with the 2,4-D herbicide in which the herbicide is broken
down into something harmless to the plant. A plant with
the gene can thereby survive application of the herbicide
while surrounding weeds do not.
     Bayer owns U.S. Patent No. 6,153,401, entitled “Mi-
croorganisms and Plasmids for 2,4-Dichlorophenoxyacetic
Acid (2,4-D) Monooxygenase Formation and Process for
the Production of These Plasmids and Strains.” The
application that eventually led to this patent was filed in
the late 1980s. By that time, scientists had discovered
that certain bacteria found in soil could grow on 2,4-D. To
do so, those bacteria first convert 2,4-D into a substance
called 2,4-dichlorophenol, or “2,4-DCP,” which the bacte-
ria, far from finding toxic, use as a “source[] of carbon and
energy.” ’401 patent, col. 3, lines 22-24; see id., col. 30,
lines 34-36. Scientists hoped that, if they identified genes
in such bacteria that coded for enzymes that catalyze 2,4-
D-to-2,4-DCP reactions, they could then transfer the
“ability to inactivate 2,4-D” to plants. Id., col. 2, lines 27-
30.
     The inventors of the ’401 patent were the first “to iso-
late, to clone, and to characterize” a gene that had that
property, a gene from the soil bacterium strain Alcali-
genes eutrophus JMP134. Id., col. 1, lines 41-61. The
patent sets forth the nucleotide sequence in Figure 10. It
is the only gene identified in the ’401 patent.
    The specification explains the “growth test” used to
isolate the identified gene. First, the inventors created a
mutant strain of the bacterium that lacked the ability to
grow on 2,4-D or convert it into 2,4-DCP. Id., col. 22, line
56, through col. 25, line 42. Next, they fragmented the
DNA of a non-mutant strain, which could still break down
2,4-D. Id., col. 24, line 18, through col. 25, line 42. They
then inserted the fragments into cells of the mutant
strain, with (roughly speaking) no two fragments in the
4            BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

same cell, and placed the cells on 2,4-D. When they
identified cells that grew, they concluded that the DNA
fragment that had restored the ability to grow on 2,4-D
contained a gene producing an enzyme that caused the
conversion of 2,4-D into 2,4-DCP. Id., col. 25, lines 38-42.
They used known sequencing techniques to identify the
nucleotide sequence of the successful fragment. Id., col.
27, line 37, through col. 29, line 4. 1
     Although this work led the inventors to the Figure 10
gene sequence, they did not fully understand the enzy-
matic reaction that they were studying. In particular, the
reaction requires the presence of the oxygen molecule, O2,
but the inventors did not know where one of the two
oxygen atoms wound up. There was no doubt about the
first: it combines with 2,4-D to create an unstable, hy-
droxylated 2,4-D, which then spontaneously splits apart
into 2,4-DCP and a compound called glyoxylate. The
patent describes this process as “bringing about the
cleavage of the side chain of 2,4-D.” Id., col. 2, lines 25-27.
As for the second oxygen atom, however, the inventors at



    1   Because the conversion of 2,4-D into 2,4-DCP was
the first step (step A) of a known multi-step process for
breaking down 2,4-D, an enzyme that catalyzes that first-
step reaction has been called a TfdA enzyme—“Tfd”
representing the initials of “two,” “four,” and “Dichloro-
phenoxyacetic Acid,” and “A” referring to step A. Similar-
ly, a gene that encodes for such an enzyme has been
called a “tfdA” gene (no initial capital, sometimes but not
always in italics). Bayer has recognized that both terms
cover categories of differing structures. See Opening Br.
at 19 (“‘TfdAs’” (plural) are “enzymes” (plural) catalyzing
the step A reaction); id. at 3 n.2 (“a ‘tfdA’ gene encodes a
‘TfdA’ side-chain-cleaving enzyme”). Sometimes, however,
the patent and other publications appear to have used the
terms to refer to the particular Figure 10 gene and its
particular enzyme product.
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC           5

best simply shared the scientific community’s unverified
belief that this atom was incorporated into water. As was
established beyond dispute in the district court in this
case, enzymes catalyzing a reaction in which one oxygen
atom ends up in water and the second is incorporated into
a product other than water are called monooxygenases,
and the ’401 patent uses the term “monooxygenase”
throughout the specification to characterize the enzyme
whose gene it sequenced. And Bayer used the term
“monooxygenase” in its claims—both alone and as part of
“2,4-D-monooxygenase”—in the 1989 continuation-in-part
application that eventually issued as the ’401 patent.
U.S. Patent Application No. 07/322,604, pp. 66-70 (filed
Mar. 10, 1989).
    Bayer’s reliance on an unverified belief about its en-
zyme soon proved wrong. In 1993, when Bayer’s applica-
tion was still pending, scientists determined that it was
incorrect to refer to Bayer’s enzyme as a monooxygenase
because the second oxygen atom does not actually end up
in water. It was, instead, a dioxygenase, because both
oxygen atoms are incorporated into products other than
water. See Fumiyasu Fukumori & Robert P. Hausinger,
Alcaligenes          eutrophus         JMP134         “2,4-
Dichlorophenoxyacetate Monooxygenase” Is an α-
Ketoglutarate-Dependent Dioxygenase, 175 J. Bacteriology
2083 (1993). Yet, despite the announcement of this
discovery in the very title of the article, and Bayer’s
knowledge of the article, Bayer did not alter the claims of
its application—which did not mature into a patent until
seven years after the 1993 discovery. Accordingly, the
’401 patent issued in 2000 with independent claim 1
reciting an artificially constructed gene as follows:
   A recombinant gene, comprising
   a DNA sequence encoding a polypeptide having
    the biological activity of 2,4-D monooxygenase
    which is capable of being expressed in a plant,
    operably linked to
6           BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

    a heterologous promoter capable of promoting the
     expression in a plant of a structural gene opera-
     bly linked thereto.
’401 patent, col. 32, lines 12-19. Dependent claim 4
claims the recombinant gene of claim 1 “wherein the DNA
sequence is the structural gene sequence of FIG. 10,
except that the initiation codon is ATG,” or certain speci-
fied variants. Id., col. 32, lines 27-34.
                             B
    Dow AgroSciences produces a line of genetically modi-
fied seeds that are resistant to 2,4-D as well as other
herbicides. Dow’s products use two genes—called aad-1
and aad-12—that code for two AAD (AryloxyAlkanoate
Dioxygenase) enzymes.       Like the enzyme of Bayer’s
patent specification, those AAD enzymes are dioxygenases
that catalyze a reaction in which 2,4-D converts to 2,4-
DCP.
    In December 2010, Bayer brought suit accusing Dow’s
seeds of infringing the ’401 patent. Although Dow’s
products do not use the Figure 10 gene, Bayer argued that
they fall within the broader claim 1, which encompasses
enzymes that “hav[e] the biological activity of 2,4-D
monooxygenase.” Bayer’s position from the outset has
been that the quoted phrase covers any enzyme that
triggers cleaving of the side chain of 2,4-D to produce 2,4-
DCP, even if it is a dioxygenase and even if it does not
share other biological activities of the particular enzyme
whose gene Bayer sequenced. Because Dow’s seeds
contain genes coding for enzymes that allegedly cause the
cleaving of 2,4-D’s side chain, Bayer contended that they
infringe.
    After holding a Markman hearing with witness testi-
mony and receiving cross-motions for summary judgment,
the district court entered judgment in Dow’s favor. See
Bayer CropScience AG v. Dow AgroSciences LLC, Civ. No.
10-1045 RMB/JS, 2012 WL 4498527 (D. Del. Sept. 27,
2012). Limiting its analysis to the “biological activity of
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC              7

2,4-D monooxygenase” phrase, the court rejected Bayer’s
view of its claims. Instead, the court concluded that the
“plain and ordinary meaning” requires that “2,4-D
monooxygenase” be read to embody the established scien-
tific meaning of “monooxygenase,” which involves one
oxygen atom going to water, and that the whole phrase
therefore means “the enzymatic activity of an enzyme, in
a biological system, that causes a reaction with 2,4-D, and
two molecules of oxygen, where one molecule of oxygen is
added to 2,4-D and the other ultimately forms water.” Id.
at *4; see id. at *3-8. Under that construction, there was
no dispute that Dow’s products do not infringe because
they are dioxygenases, even though they “create 2,4-D
resistant plants” through an enzymatic activity that
produces cleaving of the side chain of 2,4-D to yield 2,4-
DCP. Id. at *2.
    Having rejected Bayer’s “broad functional-based” con-
struction, id. at *8, the court went on to explain that, if it
had concluded otherwise, it still would have granted
summary judgment for Dow, just for a different reason.
Id. at *8-10. Specifically, the court ruled that the claim so
construed would “fail[] to satisfy the written description
requirement of 35 U.S.C. § 112” because disclosing one
gene and the test used to find it was not enough to cap-
ture the large genus that Bayer purported to have
claimed. Id. Bayer appeals. We have jurisdiction under
28 U.S.C. § 1295(a)(1).
                        DISCUSSION
    This case turns on claim construction, a matter that
we review de novo. Specifically, it turns on whether
Bayer’s proposed construction of the term “the biological
activity of 2,4-D monooxygenase” in the only independent
claim (claim 1) is correct. Bayer rests its appeal entirely
on the contention that the district court erred in failing to
construe the term broadly to mean “bringing about the
cleavage of the side chain of 2,4-D,” without further
qualification. Like the district court, we see two problems
with this position: (A) familiar aspects of textual analysis
8           BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

point strongly the other way; and (B) it would read inde-
pendent claim 1 so broadly as to raise serious doubts
about validity. Together, those problems lead us to con-
clude that Bayer’s proposed claim construction is wrong,
which leaves us with no basis for disturbing the district
court’s judgment of non-infringement of claim 1 (and
hence all dependent claims).
                             A
    To get to its construction of “the biological activity of
2,4-D monooxygenase” as “bringing about the cleavage of
the side chain of 2,4-D,” Bayer takes two steps. First, it
treats the phrase “2,4-D monooxygenase” as not carrying
the ordinary meaning of sending one of the two oxygen
atoms to water—treating it instead either as if it said
merely “oxygenase” or as if it were a proper name of a
particular enzyme (or class) without any descriptive
meaning. Second, Bayer broadens the claim coverage by
defining the term “the biological activity of” as referring
to any enzyme that alters 2,4-D by cleaving its side
chain—neither encompassing other biological activities
nor limited to those cleaving reactions that make the
enzyme a monooxygenase. Both steps encounter serious
textual difficulties.
    To begin with, these efforts fight a facially straight-
forward textual analysis. As the district court recognized,
all agree that the word “monooxygenase” has long had a
clear meaning—i.e., an enzyme catalyzing a reaction in
which one oxygen atom is incorporated into water and the
second is incorporated into something other than water.
See Bayer, 2012 WL 4498527, at *3-4. Putting “2,4-D” in
front of “monooxygenase,” then, appears to be simply the
standard way of conveying what the monooxygenase acts
on, namely, 2,4-D. And “the biological activity of,” in
turn, is naturally understood to refer to the activity that
makes the identified enzyme a monooxygenase that acts
on 2,4-D: the attachment of one oxygen atom to the 2,4-D
molecule to trigger cleaving with the other atom of O2
going to water. Under this reading, the full phrase works
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC            9

as an integrated unit in a way that fits its structure and
the ordinary meaning of its words.
     Arguing against this textual analysis, Bayer proposes
a construction that first requires stripping the phrase
“2,4-D monooxygenase” of the scientifically accepted
descriptive content of the term “monooxygenase.” Adopt-
ing Bayer’s position, we think, would require that the ’401
patent, or its history, make reasonably clear that Bayer
was not using the term in its established descriptive
sense. See, e.g., Abbott Labs. v. Syntron Bioresearch, Inc.,
334 F.3d 1343, 1355 (Fed. Cir. 2003). Familiar claim-
construction policies regarding public notice and patentee
drafting duties make it appropriate to demand such
clarity here: Bayer chose the language based on an unver-
ified belief that it accurately described its enzyme,
learned that the belief was false while its application was
pending, had seven years before its patent issued to alter
the language, but never did.
    The patent and its history, however, do not clearly in-
dicate that the patent uses the language at issue without
its accepted scientific descriptive meaning. On the con-
trary, Bayer’s usage in the intrinsic record is at the very
best inconsistent. Much of it actually reinforces the
straightforward descriptive meaning of the claim terms.
    Nothing in the intrinsic record affirmatively indicates
that, if the phrase “2,4-D monooxygenase” is descriptive,
the “mono” part is to be ignored. Perhaps Bayer should
have recognized that its background assumption that
“mono” was accurate was unverified, and initially used a
different phrase. But given its reliance on that assump-
tion, one would hardly expect the 1989 written description
to contain a redefinition to override the “mono” meaning.
    As for any understanding of the claim phrase as a
proper name whose “monooxygenase” portion lacks any
descriptive significance, the intrinsic record provides
Bayer nothing like clear support. The patent uses the
phrase or its variants in different ways, sometimes with
10           BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

an indefinite article implying a descriptive class-defining
use, sometimes with other indicators that it is describing
a genus (naturally defined by the ordinary meaning), and
only sometimes as what might seem to be just a proper
name (but even then without excluding an implication
that the name conveys the underlying mechanism of
action). E.g., ’401 patent, col. 1, lines 21-23 (“2,4-D-
Monooxygenase is an enzyme catalyzing in many 2,4-D-
degrading organisms the first step in the metabolizing of
[2,4-D].”); id., col. 2, lines 66-67 (referring to the enzyme’s
“2,4-D-monooxygenase activity”); id., col. 1, line 63 (refer-
ring to “the tfdA-encoded 2,4-D-monooxygenase,” the
adjective suggesting a narrowing of the broader class
identified by the noun). 2 The prosecution history is
similar. Notably, claims filed in the 1989 application
claimed “a 2,4-D monooxygenase gene . . . encoding a
polypeptide having the biological activity of such a
monooxygenase,” U.S. Patent Application No. 07/322,604,
pp. 66-67 (filed Mar. 10, 1989) (emphasis added)—
language that reinforces rather than undermines the
ordinary descriptive meaning.
     The conclusion we draw is that there is no clear mes-
sage that the patent gives Bayer’s broad meaning to “2,4-
D monooxygenase” in place of the term’s accepted scien-
tific meaning, which describes a particular mechanism of
action. Bayer’s usage in this court reinforces the conclu-
sion. Much of Bayer’s language continues to suggest a



     2    See also, e.g., ’401 patent, col. 25, lines 13-14 (“a
functional 2,4-D-monooxygenase”); id., col. 2, line 25
(“[t]he tfdA gene codes for 2,4-D [monooxygenase]”); id.,
col. 3, lines 5-6 (“the 2,4-D monooxygenase gene”); id., col.
7, lines 15-16 (“the tfdA-coded 2,4-D-monooxygenase”);
id., col. 8, lines 7-8 (“the 2,4-D-monooxygenase activity”);
id., col. 25, lines 53-56 (“[p]lasmids . . . containing an
intact tfda gene . . . can produce 2,4-D-monooxygenase in
large amounts”).
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC           11

class-defining descriptive meaning. See note 1, supra;
Opening Br. at 14 (claim 4 “recites the DNA sequence of
one exemplary 2,4-D monooxygenase”); Reply Br. at 4
(“specification also unambiguously refers to a genus of
genes encoding a genus of ‘2,4-D monooxygenases’”);
Opening Br. at 15 (“One claim phrase is at issue here:
‘biological activity of a 2,4-D monooxygenase.’”).
    Bayer’s argument regarding the “biological activity”
language of claim 1 is likewise unpersuasive. As the
district court recognized, the ordinary meaning of that
phrase alone places no particular limit on what kinds of
activities in living cells are covered. See Bayer, 2012 WL
4498527, at *3-4. As indicated above, a natural narrow-
ing is provided by giving “monooxygenase” its “mono”
meaning: the “biological activity” would be that activity
which makes the enzyme a monooxygenase. But Bayer
rejects both the all-biological-activities meaning and the
premise of the narrowing integrated interpretation.
Instead, it argues that the specification “defines” the
“biological activity” claimed to be “bringing about the
cleavage of the side chain of 2,4-D,” no more and no less.
We disagree.
    The specification uses the phrase “biological activity”
just twice. Bayer focuses heavily on the first appearance,
which says: “The tfdA gene codes for 2,4-D monooxygen-
ase, a polypeptide having the biological activity of bring-
ing about the cleavage of the side chain of 2,4-D.” ’401
patent, col. 2, lines 25-27 (as corrected by certificate of
correction). That language does not have the form of, or
otherwise convey that it is, a definition of “the biological
activity.” It describes something that a “2,4-D monooxy-
genase” does, but it does not say that every enzyme with
that function is a “2,4-D monooxygenase.” See Bayer,
2012 WL 4498527, at *5. More is needed for a term with
an established scientific meaning to be redefined in the
specification.
     The specification’s second reference to “biological ac-
tivity” actually works against Bayer’s argument. In the
12          BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

same column, the patent refers to “coding for a protein
which has the biological activity of the protein encoded by
tfda, e.g., its 2,4-D-monooxygenase activity.” ’401 patent,
col. 2, lines 65-67. The use of “e.g.,” rather than “i.e.,”
strongly suggests that there is more than one “biological
activity.” And “its 2,4-D monooxygenase activity” sug-
gests the activity that makes it a monooxygenase.
    In short, as the district court explained, the claim
language has a strong accepted scientific meaning.
Bayer’s alternative construction strips the monooxygen-
ase half of the claim phrase of its accepted descriptive
meaning and then asserts a specification “definition” of
the biological-activity half. We do not find enough in the
specification or prosecution history to justify those steps.
                             B
    Bayer’s construction has not only textual problems. It
goes far beyond the Figure 10 enzyme, beyond monooxy-
genases, beyond enzymes produced by bacteria found
mainly in soil, to capture the broad functionally defined
genus of enzymes that cause cleaving of the 2,4-D side
chain. This broad reading would call into serious doubt
the claim’s validity under 35 U.S.C. § 112(a). See Bayer,
2012 WL 4498527, at *8-10.
    In this case, which is not one in which a patentee in-
vokes invalidity considerations to support a narrowing
construction, Bayer seeks a broad construction of its own
patent, and the alleged infringer Dow has raised invalidi-
ty problems with that construction. A record regarding
those problems was extensively developed at the same
time as the record for claim construction. In these cir-
cumstances, it is both possible and sensible to find that
such grave doubts reinforce the textual objections to
Bayer’s proposed construction. This court’s decision in
Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005),
while observing that “validity analysis is [not] a regular
component of claim construction,” leaves room for reliance
on this bolstering consideration where, as here, the record
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC          13

on invalidity is sufficiently developed to establish grave
validity doubts under the court’s standards. Id. at 1327-
28. 3
    Bayer’s proposed construction broadly covers a class
of enzymes defined by their function of causing cleaving of
the side chain of 2,4-D, while its written description
structurally identifies just one gene sequence and the
enzyme it encodes. We have not articulated a comprehen-
sive and precise formulation for identifying when such a
combination runs afoul of Section 112(a)’s written-
description requirement; indeed, we have counseled
against “bright-line rules” in this area. Ariad Pharms.,
Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir.
2010). But we have indicated the primacy of structural
identification for inventions in certain areas like the one
at issue here, and when we have adverted to the possibil-
ity of other means of identification, we have focused on
whether such alternative means sufficiently correlate
with structure. See, e.g., Novozymes A/S v. DuPont
Nutrition Biosciences APS, No. 2012-1433, 2013 WL
3779376, at *14 (Fed. Cir. July 22, 2013); Ariad, 598 F.3d
at 1350; Carnegie Mellon Univ. v. Hoffman-La Roche Inc.,
541 F.3d 1115, 1121, 1124 (Fed. Cir. 2008); Univ. of
Rochester v. G.D. Searle & Co., Inc., 358 F.3d 916, 925
(Fed. Cir. 2004) (“functional descriptions of genetic mate-
rial can, in some cases, meet the written description
requirement if those functional characteristics are ‘cou-
pled with a known or disclosed correlation between func-
tion and structure, or some combination of such
characteristics’”) (quoting Enzo Biochem, Inc. v. Gen-
Probe Inc., 323 F.3d 956, 964 (Fed. Cir. 2002)); Regents of



   3    We identify the circumstances here simply to de-
fine what we are deciding, which leaves open to argument
in a different case whether the same conclusion, or a
different conclusion, would be warranted in circumstances
different from those presented here.
14          BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

Univ. of Cal. v. Eli Lilly & Co., 119 F.3d 1559, 1566, 1569
(Fed. Cir. 1997) (discussing situation where patent de-
scribes a “representative number” of species).
    The coverage of claim 1 that Bayer proposes would
leave the ’401 patent far from providing even an indirect
structural identification of all that would be within the
claim’s scope. The enzymatic function—under Bayer’s
construction, causing the cleaving of the side chain of 2,4-
D—would be broad, yet the patent provides the DNA
sequence (and hence amino-acid sequence) of just one
embodiment. As the district court explained, Bayer, 2012
WL 4498527, at *9-10, neither the patent nor the
knowledge in the art showed that what Bayer offered in
place of a description of the shared structure—the growth
test—correlated closely with an enzyme’s structure. The
patent provided what was “[a]t best . . . a roadmap [that
would] ‘leav[e] it to the . . . industry to complete [the]
unfinished invention.’” Novozymes, 2013 WL 3779376, at
*14. Moreover, the “roadmap” told a person of ordinary
skill how to find some, perhaps even many, but not all
members of the genus claimed under Bayer’s broad con-
struction, because enzymes not found in soil bacteria may
catalyze 2,4-D-degrading reactions but could not be dis-
covered (reliably or perhaps at all) using the growth test.
    At oral argument in this court, Bayer has sought to
mitigate this concern by expressly arguing that any genes
not derived from soil bacteria would fall outside of the
claimed genus. But Bayer did not present a claim con-
struction based on that trimming effort to the district
court, or even in its opening brief in this court. Rather
than undertake to show how a “soil” limitation could be
justified, Bayer argued for its broad construction, which
contains no such limitation. Bayer, 2012 WL 4498527, at
*3; Opening Br. at 6. Only Bayer’s proposed construction,
not a belated narrowing construction, is at issue. And the
significant invalidity troubles that accompany Bayer’s
construction substantiate our rejection of it.
BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC            15

                             C
    Neither party has presented us with a reason to go
beyond rejecting Bayer’s proposed claim construction.
Our rejection of Bayer’s construction settles the question
of non-infringement and thus provides us with sufficient
grounds for affirming summary judgment in Dow’s favor.
In other cases, this court has limited its claim-
construction analysis to go no further than was required
to affirm or otherwise rule on the judgment appealed.
See, e.g., Verizon Servs. Corp. v. Vonage Holdings Corp.,
503 F.3d 1295, 1305 (Fed. Cir. 2007); Rheox, Inc. v. En-
tact, Inc., 276 F.3d 1319, 1324-25 (Fed. Cir. 2002); see also
Leo Pharm. Prods., Ltd. v. Rea, No. 2012-1520, 2013 WL
4054937, at *5 (Fed. Cir. Aug. 12, 2013). We take the
same approach here. Bayer has not timely argued that it
can prevail without the adoption of its broad construction,
and we need not affirmatively construe the claims in
order to affirm the district court’s judgment.
    Dow has offered two alternative constructions. Dow
primarily defends the district court’s construction, which
reads claim 1 on its own terms and limits it to genes
coding for “monooxygenases.”         See Bayer, 2012 WL
4498527, at *3-8. Dow also suggests a second, much
narrower construction that would limit the claims by
reference to the specific Figure 10 gene sequence.
     The first of those alternatives is strongly supported by
the most natural reading of the claim language, as we
have explained. On the other hand, it excludes the specif-
ic gene based on Figure 10 that was Bayer’s core inven-
tion. While that result is generally disfavored, there is no
absolute rule against it, Lucent Technologies, Inc. v.
Gateway, Inc., 525 F.3d 1200, 1215-16 (Fed. Cir. 2008),
and skilled artisans would readily understand the expla-
nation here, namely, Bayer’s initial mistaken belief about
its enzyme’s properties and then its insistence on retain-
ing claim language reflecting that belief even after it was
known to be false. The second of Dow’s interpretations
offers the advantage of protecting Bayer’s specific se-
16          BAYER CROPSCIENCE AG   v. DOW AGROSCIENCES LLC

quencing invention. But the claim most tailored to that
important advance, claim 4, is not a free-standing one; it
is written as a dependent claim, thus requiring satisfac-
tion of claim 1, whose language therefore must be proper-
ly construed. Moreover, it is hardly unknown for a
patentee with an invention that could be protected to fail
in securing such protection by bad choices in claim draft-
ing. See, e.g., Chef Am., Inc. v. Lamb-Weston, Inc., 358
F.3d 1371, 1374 (Fed. Cir. 2004); Elekta Instrument S.A.
v. O.U.R. Scientific Int’l, Inc., 214 F.3d 1302, 1308-09
(Fed. Cir. 2000).
     We do not have to address the issues raised by the al-
ternatives proffered by Dow. Nor do we have before us
any other construction that Bayer might propose in
another case. We need not say whether some narrower
construction, if timely offered and defended by Bayer,
would have enough to recommend it to overcome the
difficulties we have found decisive against its broad
construction. All we need and do say is that, because we
do not accept the only claim construction under which
Bayer has alleged infringement, we affirm the summary
judgment of non-infringement.
                      AFFIRMED
