Broadening Claim Language in Gene Patents

The claims define the scope of a patent. There are different types of claim language that are used in gene-based patents and patent applications that broaden the scope of the claim beyond the actual sequences that are disclosed in a specification. For the purposes of this landscape, we refer to this type of claim language as “broadening language”.

Hybridisation Language

Hybridisation language in claims allows an applicant to claim a particular nucleotide sequence, as well as any nucleotide sequence that hybridises to that sequences under a given set of experimental conditions. See a tutorial on the basis for hybridisation language for a more detailed description. An example of a claim with hybridisation language is claim 1 from US Patent No. 5747327:

A cloned DNA which encodes phospholipase D originated from a plant, wherein said DNA comprises a nucleotide sequence selected from the group consisting of nucleotides 182-2617 of SEQ ID NO:1 and nucleotides 107-2542 of SEQ ID NO:3 or a sequence complementary thereto or a sequence which specifically hybridizes to said cloned DNA or said complementary sequence in a hybridization solution containing 0.5M sodium phosphate buffer, pH 7.2, containing 7% SDS, 1 mM EDTA and 100 mg/ml of salmon sperm DNA at 65° C. for 16 hours and washing twice at 65° C. for twenty minutes in a washing solution containing 0.5×SSC and 0.1% SDS.

Percent Identity Language

Percent identity language, which is also sometimes expressed as percent similarity language, allows an applicant to claim not only the sequence of interest, but any sequence that is for example, 70, 80, or 90% identical to that sequence. This dramatically broadens the scope of the claim by increasing the number of individual sequences that meet the criteria of the claim. Percent identity or similarity language may be used with either nucleotide and amino acid sequences.

A potential difficulty with determining the meaning of a claim with percent identity language is that applications do not always specify the parameters for calculating the percent identity. There are many different algorithms that may be used to determined how similar sequences are to each other. Many algorithms assign different values for gaps in sequences that can affect the overall percent score in a variety of ways.

Such claims are not often granted these days. Unless examples of related sequences are specified in the patent and furthermore are shown to have similar function, they are not usually allowed.

For example, the first claim of US Patent No. 6821764:

  1. An isolated nucleic acid fragment encoding a serine O-acetyltransferase comprising: (a) a nucleotide sequence encoding a polypeptide having serine O-acetyltransferase activity, wherein the polypeptide has an amino acid sequence of at least 95% sequence identity, based on the cluster, when compared to SEQ ID NO: 8 or (b) a full complement of the nucleotide sequence of (a).

Amino Acid Substitutions

Some applications include claim language reciting particular amino acid substitutions.   For example, claim 1 from US Patent No. 7057088:

An isolated DNA encoding a protein selected from the group consisting of
(a) a DNA encoding a protein comprising the amino acid sequence set forth in SEQ ID NO: 1,
(b) a DNA comprising the nucleotide sequence from position 54 to 1199 set forth in SEQ ID NO:2, and
(c) a DNA encoding a protein comprising the amino acid sequence set forth in SEQ ID NO:1,
wherein one to 10 amino acid residues are substituted, deleted, added, and/or inserted and wherein said protein:
(i) has gibberellin 2β-hydroxylase activity; and
(ii) conserves amino acids corresponding to His-241, Asp-243 and His-302 in the amino acid sequence set forth in SEQ ID NO:1.

Claiming Any Nucleotide Sequence that Encodes a Specified Amino Acid Sequence

One common way to capture a nucleotide sequence is provide the SEQ ID NO of an amino acid and word the claim such that any nucleotide sequence that encodes that amino acid sequence is claimed. Because the genetic code is degenerate, such a claim encompasses a very large number of nucleic acid sequences.

For example, the first claim of US Patent No. 7268271

A method for increasing LEC1 expression in a plant cell, wherein said increase is measured against a control plant cell, said method comprising introducing an isolated LEC1 nucleic acid into the plant cell to produce a plant cell that exhibits increased LEC1 expression, wherein the isolated LEC1 nucleic acid comprises a member selected from the group consisting of (a) a polynucleotide which encodes a polypeptide of SEQ ID NO: 2;(b) a polynucleotide of SEQ ID NO: 1; and(c) a polynucleotide complementary to a polynucleotide of (a) or (b).

SEQ ID NO:2 is purely an amino acid sequence, and thus all nucleic acids coding for this sequence are covered by this claim.