Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Status
Amendment to the claims filed 22 Jun 2026 are acknowledged. Claims 89-90, 93, 97-98, 108, and 119-120 are newly amended. Claims 95-98, 100, 108-111, 119-120, and 122-125 were previously withdrawn. Claims 1-88, 91, 99, 101-107, 112-118, and 121 were previously canceled. Claims 89-90 and 92-94 are pending and under consideration.
Drawings
Objections to the drawings are withdrawn due to amendments to the drawings.
Maintained-Claim Rejections - 35 USC § 112(a)
The following is a quotation of the first paragraph of 35 U.S.C. § 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Rejection of claims 89-90 and 92-94 under 35 U.S.C. § 112(a) with respect to interspecies crosses are withdrawn due to amendment to the claims.
Grounds of rejection regarding Issue 2 (as numbered in the Office Action mailed 24 Mar 2026) are withdrawn due to amendments to the claims, which now require that the first and second non-human vertebrate are the same species. The claims remain rejected with regard to Issues 1, 3, and 4 raised in the Office Action mailed 24 Mar 2026. Numbering of the issues is maintained for clarity and consistency across Office Actions although Issue 2 is no longer present in the rejection.
Claims 89-90 and 92-94 remain rejected in modified form under 35 U.S.C. § 112(a) as failing to comply with the enablement requirement. The claims contain subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention. The grounds of rejection are modified as necessitated by amendments to the claims.
Enablement is considered in view of the Wands factors (MPEP 2164.01(a)). The court in Wands states, “Enablement is not precluded by the necessity for some experimentation such as routine screening. However, experimentation needed to practice the invention must not be undue experimentation. The key word ‘undue’, not ‘experimentation.’” (Wands, 8 USPQ2d 1404). Clearly, enablement of a claimed invention cannot be predicated on the basis of quantity of experimentation required to make or use the invention. "Whether undue experimentation is needed is not a single, simple factual determination, but rather is a conclusion reached by weighing many factual considerations." (Wands, 8 USPQ2d 1404). When determining whether a specification meets the enablement requirement, some of the factors to be analyzed are: (1) the breadth of the claims, (2) the nature of the invention, (3) the state of the prior art, (4) the level of one of ordinary skill in the art, (5) the level of predictability in the art, (6) the amount of direction provided by the inventor, (7) the existence of working examples, and (8) whether the quantity of any necessary experimentation to make and use the invention based on the content of the disclosure is undue (Wands). While all of these factors are considered, those sufficient for establishing a prima facie case are discussed below.
Nature of the invention
The claimed invention relates to a method of synthetic lethality to generate single sex progeny for uses in which a single sex is required or highly desired, such as in agriculture for dairy, egg, and meat production or in research for sex-specific physiology and disease. The claimed invention involves generating transgenic parents carrying nucleotide sequences encoding toxin fragments inherited in a sex-specific manner. Progeny of the transgenic parents are viable if they inherit a single toxin fragment but are not viable if they inherit both toxin fragments.
Breadth of the claims
Issue 1: The breadth of the claims with respect to “the non-human vertebrate animal” encompasses tens of thousands of vertebrate species and two different chromosomal systems for sex determination, the XX/XY and the ZZ/ZW chromosome systems (B. Capel, Nat Rev Genetics, 2017, pp. 676-685, hereafter Capel). Most, but not all, mammals use the XX/XY chromosome system, in which XX individuals are female and XY individuals are male (Capel, pp. 676-677). Birds and snakes use the ZZ/ZW chromosome system, in which ZZ individuals are male and ZW individuals are female (Capel, p. 677). The claims are drawn to insertion of the sequences for the first and second toxin onto chromosomes determinative of sex, which therefore limits insertion on the Z, W, X, and Y chromosomes.
Issue 3: The breadth of the claims with respect to the functional toxin encompasses any toxin lethal to a cell, which represents a vast array of structurally and mechanistically diverse compounds. No sequence, structural component, or locus with a sex chromosome is recited for the first and second toxin fragments. Furthermore, the nuclease recited in claim 93 and the Barnase, RNase, and restriction endonuclease recited in claim 94 are broad in these nucleases encompass toxic, but non-lethal nucleases.
Existence of working examples
The specification provides Example 1 and Example 2 as prophetic examples (pp. 32-33). However, both Example 1 and Example 2 are drawn to non-elected inventions. No working example, prophetic or otherwise, is provided for the elected invention. No indication is given that any part of the claimed invention has been attempted.
Amount of direction provided by the inventor
The specification only discloses a generic approach to producing a single sex population of non-human vertebrates via first and second toxin fragments. The specification does not provide direction related to the missing elements noted above discussed under Breadth of the claims.
Issue 4: The claims do not include active steps or structural elements to suggest how the first and second toxin fragments combine to result in a non-viable progeny. The only direction given for how two non-lethal toxin fragments might give rise to lethal toxicity relate to a non-elected invention, split intein fragments (Example 1, par. 141-148). For a toxin to lead to lethality, there must be sufficient dosing in the correct context, e.g., expression in a cell necessary for survival of the embryo/fetus, to produce nonviable progeny. No direction is provided for the timing, gene dosage, or expression pattern required to achieve lethal toxicity.
State of the prior art
As of the earliest effective filing date of the immediate application, 16 Sep 2022, the art teaches genetic methods for synthetic lethality to generate single sex progeny (C. Douglas and J.M.A. Turner, PLOS Genet, 2020, cited in IDS, hereafter Douglas 2020). The most relevant of such methods involve splitting the genetic components required for synthetic lethality onto chromosomes separately inherited from both parents (Douglas 2020, Fig. 1c and pp. 4-12). However, such methods are based on knocking out or mutating genes required for development rather than expressing a toxin (Douglas 2020, pp. 4,6 and Fig.1). Methods of expressing a transgene to generate a toxin has been limited to use in insects (Douglas 2020, pp. 4,6 and Fig. 1). The art does not teach splitting induced toxins into fragments. Therefore, a skilled artisan attempting to make or use the claimed invention would have to translate methods practiced in insects to a vast number of vertebrate species without direction from the art or from the inventor. Particularly, the art does not teach how two separate, non-lethal toxin fragments can become lethal just because the nucleic acids encoding two toxin fragments are found within the same animal.
Unpredictability in the prior art
With respect to Issue 1, Douglas 2021 (C. Douglas, et al., Nat Commun, 2021) teaches two major hurdles when practicing the claimed invention in mammals. First, “transgenes on the X chromosome are susceptible to silencing”. (Douglas 2021, p. 2). Second, transgenes “on the Y chromosome are repressed by its heterochromatic state” (Douglas 2021, p. 2).
With respect to Issue 3, an example of a toxic nuclease encompassed by the breadth of the claims is zinc finger nucleases, which are artificial restriction endonucleases used for gene editing. Zinc finger nucleases have known genotoxicity due to cleavage at off-target sites in the genome (T.I. Cornu, Methods Mol Biol, 2010, p. 237, hereafter Cornu). However, even given this toxicity, zinc finger nucleases can be introduced to and expressed in cells without lethality (Cornu, p. 237). A toxin is not necessarily lethal, and toxins capable of inducing lethality are not lethal in all circumstances.
With respect to Issue 4, the claims do not include active steps or structural elements to suggest how and under what conditions the toxin fragments are lethal. For example, the toxin fragments may be under control of a promoter that limits expression to gonadal cells, which would only lead to lethality in cells not required for viability of the animal. Lethality of a toxin is determined by dosage, localization to cells and tissues required for survival, and insufficiency in homeostatic mechanisms to neutralize or excrete the toxin. Particularly for the present invention, lethality of the toxin(s) must also be limited in timing such that lethality is induced in early development before birth/hatching. When the claimed invention is practiced in vertebrates that gestate the fetus to term, such as mammals, the dosing and timing of lethal toxicity must also be limited so as to not kill littermates or the pregnant mother, which would render the claimed invention inoperable (Douglas 2020 p. 11 and Douglas 2021 p. 2). Achieving these limits on feasibility is further complicated by the requirement to achieve toxic lethality using two toxin fragments acting in concert, which is not taught in the art.
Quantity of experimentation required
As discussed above, the claims are broad with respect to species of both the first and second non-human vertebrate animal, the system of sex determination in the chosen species, the identity and relationship between the first and second toxin fragments, the mechanism by which the first and second toxin fragments induce lethality, and whether or how the toxin fragments are expressed and in what conditions. Furthermore, methods of synthetic lethality based on expression of a toxin has not been applied to vertebrates, much less methods based on toxin fragments. To make and use the claimed invention, a skilled artisan would have to test an incalculable number of combinations of embodiments, overcome barriers in multiple scientific fields, and translate findings from insects to vertebrate.
Conclusions
One of ordinary skill in the ordinary would be unable to make and use the claimed invention. There is no connection between the inheritance of the first and second toxin fragment and induced lethality. Furthermore, the claims are extremely broad and encompass a vast number of non-enabled embodiments, and the art teaches barriers to genetic methods of synthetic lethality. The specification fails to provide direction or working examples of the claimed invention. Given the breadth of the claims and the lack of direction from the inventor and from the art, a skilled artisan would be faced with the burden of undue experimentation when attempting to make and use the claimed invention.
§ 112(a) - Response to Arguments
Grounds of rejection regarding Issue 2 (as numbered in the Office Action mailed 24 Mar 2026) are withdrawn due to amendments to the claims, which now require that the first and second non-human vertebrate are the same species.
Applicant argues that amendments to the claims overcome Issues 1, 3, and 4. Regarding Issue 4, Applicant further argues that specification provides sufficient guidance as exemplified by Example 1 and that the example provides a reasonable correlation to the full scope of the claim. Applicant further argues that a Barnase, RNase, or restriction endonuclease are cytotoxically lethal and, therefore, claims 93-94 are enabled.
In response, Applicant's arguments have been fully considered but are not persuasive.
Note that any deficiencies pointed to in the Wands factor analysis are used to illustrate why the claims, the specification, or the prior art as a whole do not provide sufficient detail or teachings for a skilled artisan to discern how to perform the full scope of the claimed invention, not to attack individual aspects of the claims or the disclosure.
Enablement issues are only partially resolved by amendment regarding Issues 1 and 3 and are not resolved regarding Issue 4.
Regarding Issue 1, amended claims require that the first and second toxin fragments be located on chromosomes that are determinative of sex (p. 9 2nd par. of Remarks). Applicant argues that the amendment overcomes Issue 1 because the claims are now limited to species relying on ZW or XY chromosomes for sex determination (p. 10 last par. and p. 11 lines 1-2 of Remarks).
In response, Applicant's arguments have been fully considered but are not persuasive.
The amendment narrows the breadth of the claims to exclude species in which chromosomes are not the basis for sex determination. Inclusion of the limitation, "determinative of sex" now excludes species in which chromosomal inheritance pattern is not the only factor in sex determination. However, the scope of the claims still encompass mammals, which use an XY chromosome system for sex determination. As previously noted and maintained, the full scope of the claims are not enabled due to due the unpredictable nature of transgene silencing on the X and Y chromosomes in mammals. This issue is not fully addressed or overcome.
Regarding Issue 3, amended claims require that the first and second toxin fragments be fragments of the same toxin (p. 9 2nd par. of Remarks). Applicant argues that the amendment overcomes Issue 3 (p. 11 lines 23-24 of Remarks).
In response, Applicant's arguments have been fully considered but are not persuasive.
The amendment narrows the scope of the claim to exclude many non-enabled embodiments but does not resolve the issue. The identity of the functional toxin itself is overly broad. The issue is not merely whether the toxin is capable of killing the cell in which it is expressed, but whether the toxin is predictably cytotoxic.
As noted previously, the presence of inoperative embodiments within the scope of a claim does not necessarily render a claim non-enabled. However, the standard is whether a skilled person could determine which embodiments that were conceived, but not yet made, would be inoperative or operative with expenditure of no more effort than is normally required in the art. Atlas Powder Co. v. E.I. du Pont de Nemours & Co., 750 F.2d 1569, 1577, 224 USPQ 409, 414 (Fed. Cir. 1984). Claims reading on significant numbers of inoperative embodiments render claims non-enabled when the specification does not clearly identify the operative embodiments and undue experimentation is involved in determining those that are operative. Atlas Powder Co. v. E.I. duPont de Nemours & Co., 750 F.2d 1569, 1577, 224 USPQ 409, 414 (Fed. Cir. 1984); In re Cook, 439 F.2d 730, 735, 169 USPQ 298, 302 (CCPA 1971). See MPEP 2164.08(b).
An example from the prior art regarding lack of predictability is provided regarding zinc finger nucleases, a species of restriction endonuclease encompassed by the claims. As taught by Cornu, zinc finger nucleases can be sufficiently cytotoxic to kill cells but are not toxic in all circumstances. The claims encompass a vast array of toxins that can be cytotoxic, but the conditions in which they induce cell death are not fully elaborated in the prior art, and specific directions are not provided in the specification to overcome such limitations identified in the art as unpredictable. The issue of functionality of the toxin is further discussed under Issue 4.
Regarding Issue 4 and the amount of direction provided by the inventor, amended claims require that the functional toxin generated by expression of both of the first and the second toxin fragments is cytotoxically lethal (p. 9 2nd par. and p. 12 2nd par. of Remarks).
Applicant argues that the specification provides at least one example, Example 1, that provides a method that support the full scope of the amended claims (p. 12 4th par. of Remarks).
In response, Applicant's arguments have been fully considered but are not persuasive.
Amendments to the claims resolve issues related to whether the toxin fragments themselves are cytotoxic and whether expression of the toxin fragments is required for toxicity. However, issues regarding how the fragments combine and timing, gene dosage, or expression pattern required to achieve lethal toxicity are not addressed.
As noted previously, the only means for toxin fragment joining recited in the specification is split intein fragments. The claims are far broader and encompass any mechanism of toxin fragment combination at the protein level or combination of nucleic acids encoding the toxin fragments prior to translation. As noted by applicant, MPEP § 2164.01 states that "[a]s long as the specification discloses at least one method for making and using the claimed invention that bears a reasonable correlation to the entire scope of the claim, then the enablement requirement of 35 U.S.C. 112 is satisfied. In re Fisher, 427 F.2d 833, 839, 166 USPQ 18, 24 (CCPA 1970)". Importantly, there must be a reasonable correlation to the entire scope of the claim. Discussion of a single means of practicing the invention at a high level of generality is insufficient to provide direction for practicing the entire scope of the claim. The specification merely states that the toxin fragments can be combined and that split inteins are one means of doing so. Other means of combining toxin fragments rely on entirely different mechanisms to join protein fragments, each with its own design issues. Furthermore, the identity of toxins encompassed by the scope of the claims, as discussed under Issue 3, are also too structurally diverse for mere statements of applicability to act as direction to practice the entire scope of the claim.
Regarding Issue 4 and the existence of working examples, Applicant notes that reduction to practice is not required to meet the enablement requirement and argues that prophetic Example 1 "contains sufficient procedures and materials" for a skilled artisan to practice the full scope of the amended claims (pp. 12 last two lines – p. 13 lines 1-6).
In response, Applicant's arguments have been fully considered but are not persuasive.
Applicant is correct that working examples are not required. The existence of working examples is relied upon as one of several factors in determining whether the claims meet the enablement requirement. It is improper to conclude that a disclosure is not enabling based on an analysis of only one of the above factors while ignoring one or more of the others. The examiner’s analysis must consider all the evidence related to each of these factors, and any conclusion of non-enablement must be based on the evidence as a whole. See MPEP § 2164.01(a). The absence of a working example is merely pointed to in the rejection because working examples can provide proof that at least one embodiment of the claimed invention is feasible and provide evidence regarding which aspects of the claimed invention do or do not require further direction from the specification or prior art to practice the full scope of the invention.
Regarding Issue 4 and quantity of experimentation needed to make or use the invention, Applicant argues that the specification provides sufficient direction that a skilled artisan making and using the full scope of the invention would face an undue burden of experimentation (p. 13 2nd par. of Remarks). Applicant points to the application-in-suit in In re Angstadt, wherein the Court reversed a rejection under § 112(a) and found the quantity of experimentation was not undue (p. 13 2nd par. of Remarks). Applicant argues that in accordance with the Court's holdings in In re Angstadt, a skilled artisan would be able to follow guidance from the specification and the prior art to make and use the full scope of the claims without undue burden (p. 13 last par. – p. 14 lines 1-3).
In response, Applicant's arguments have been fully considered but are not persuasive.
Arguments of counsel alone cannot take the place of evidence in the record once an examiner has advanced a reasonable basis for questioning the disclosure. See MPEP § 2164.06. Multiple specific issues were raised in the rejection regarding undue burden of experimentation, none of which are addressed in the arguments or by way of amendment. Mere statements that a skilled artisan may use direction provided by the inventor or publicly available sources are insufficient to overcome the rejection when barriers in the prior art not addressed by the Applicant's disclosure have been identified.
Furthermore, the facts of In re Angstadt are non-analogous to the present rejection. The specification discussed in Angstadt provides 40 working examples, from which a skilled artisan can perform simple experiments to identify a new catalyst. The level of experimentation in Angstadt is limited to making a single choice regarding a catalyst. Whereas in the present application, no working example is provided, nor is any analogous art available. As previously noted, synthetic lethality based on expression of a toxin has not been practiced in vertebrates at all, much less based on toxin fragments. In the present case, a skilled artisan attempting to make or use the claimed invention must test every single element of a complex system in the art of generating transgenic animals, which is a highly unpredictable art. Experimentation in the present case is undue because the skilled artisan must design their own system with only generic guidance from the specification.
Regarding Issue 4 and the cytotoxicity of nucleases, Applicant notes that amendment to the claims to require that the functional toxin is cytotoxically lethal to the cell of the progeny (p. 9 2nd par. of Remarks) limits the scope of the claims to nucleases, including barnase, RNases, and restriction endonucleases that are cytotoxically lethal to the cell of the progeny (p. 14 lines 14-21).
Applicant provides Leuchtenberger (S. Leuchtenberger, et al. Nucleic Acids Res, 2001), Haigis (M.C. Haigis, et al. Nucleic Acids Res, 2003), and Manivasakam (P. Manivasakam, et al. Nucleic Acids Res, 2001) as a examples of using barnase, RNases, and restriction endonucleases, respectively, for inducing cytotoxicity. Applicant argues that, based teachings from the prior art, that skilled artisan would recognize that expression of barnase, an RNase, or a restriction endonuclease is lethal to a cell (p. 14 lines 22-29 and p. 15 lines 1-7).
In response, Applicant's arguments have been fully considered but are not persuasive.
The conditions in which synthetic lethality can be achieved are not addressed. As previously discussed and maintained, practice of the claimed invention must be balanced so as to induce lethality in a manner that results in destruction of undesired progeny without killing the damn or the rest of a litter.
Furthermore, the provided references are practiced in a manner insufficient to teach a skilled artisan how to make and use to the claimed invention. Leuchtenberger teaches a transgenic mouse in which expression of a barnase is under control of a transcription factor and does not involve placing the barnase transgene on a sex chromosome or splitting the barnase into fragments (Discussion p. 5). Haigis and Manivasakam teach toxicity issues in cultured cells, not in transgenic animals (Abstracts and throughout). The issue is not whether nucleases can induce lethality. The issue is whether a skilled artisan would need to redesign a nuclease to include an exogenous split site such that the fragments are not toxic and that recombine at a high fidelity when desired so as to be cytotoxic when recombined, to identify a locus on the X and/or Y chromosomes to avoid suppression of expression by the XCI complex on the X chromosome or tight chromatin packing on the Y chromosome, to identify a promoter for toxin fragments so that they are expressed at a level high enough to induce lethality in vivo and to not be so toxic so to kill the damn and litter mates, which would result in no single sex offspring at all, and to predict whether all of these issues would predictably translate when practicing in a new species. Each of these issues are identified in the prior art and discussed in the rejection above.
Claim Rejections - 35 USC § 112(d)
The following is a quotation of 35 U.S.C. § 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 90 remains rejected under 35 U.S.C. § 112(d) as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends or for failing to include all the limitations of the claim upon which it depends. The rejection is modified as necessitated by amendment to the claim. An allosome is, by definition, a chromosome that is determinative of sex, as noted in the specification (par. 34). Therefore, elaboration, “wherein the pair of homozygous chromosomes or the pair of heterozygous chromosomes are a pair of allosomes”, does not add limitations to claim 90 that are not already present in claim 89, which requires that the heterozygous chromosomes of the first non-human vertebrate and homozygous chromosomes of the second non-human vertebrate animal are determinative of sex. Applicant may cancel the claim, amend the claim to place it in proper dependent form, rewrite the claim in independent form, or present a sufficient showing that the dependent claim complies with the statutory requirements.
§ 112(d) - Response to Arguments
Amendment to claim 90 is insufficient to overcome the rejection. The issue remains that dependent claim 90 merely restates a claim limitation recited in the independent claim but using different words.
Conclusion
No claim is allowed.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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Eric B Wright, PhD
Examiner
Art Unit 1632
/Eric B Wright/Examiner, Art Unit 1632
/PETER PARAS JR/Supervisory Patent Examiner, Art Unit 1632
