In T 923/92 (OJ 1996, 564 - see also 2.1.5 b) above), claim 1, the subject-matter of which was defined by means of a reference to the amino acid sequence of Figure 5, was held not to be entitled to priority from earlier applications P1 and P2, in which that amino acid sequence was not disclosed. The sequence reported in Figure 5 was observed to differ from that of Figure 5 of P1 and P2 in respect of three amino acids. In the board's judgment, the skilled person would consider the reference to the amino acid sequence of a protein as a primary technical feature linked to the character and nature of the product. Evidence from the patentee was restricted to the testing of a limited number of parameters and constituted at most proof of similarity, not of identity of the two polypeptides. These differed in one essential characteristic, i.e. the primary amino acid sequence.
In T 351/01 a polynucleotide which was the subject-matter of claim 1 was characterised both in structural terms and by its function. Priority documents I and II disclosed a polynucleotide having the same function as that of the polynucleotide of claim 1. However, its structure differed from that of the polynucleotide of claim 1 by five bases, all found in the part of the sequence which does not relate to the function i.e. outside of the coding region. The board, referring to the Enlarged Board's opinion which had rejected an extensive or broad interpretation making a distinction between technical features which are related to the function and effect of the invention and technical features which are not, concluded that the subject-matter of claim 1 could not be seen as the same subject-matter as that disclosed in the priority documents.
In T 30/02 the board held that the presence of two additional guanine residues in the nucleotide sequence disclosed in an application cited in this case under Art. 54(3) EPC 1973 resulted in a different molecule that was not directly and unambiguously derivable from the earlier application from which priority was claimed. It was generally acknowledged in the case law of the boards of appeal that the nucleotide sequence of a nucleic acid represents an essential feature linked to the character and nature of the nucleic acid as such, and, where the nucleotide sequence is a coding sequence, also of the encoded protein (see T 923/92, OJ 1996, 564). The skilled person was aware of the fact that even a minimal modification of the nucleotide sequence may result in a different nucleic acid not only from the structural but also from the functional point of view. See also decision T 70/05.
In T 1213/05 the invention related to the human BRCA1 gene isolated from the genome and its use in the diagnosis of predisposition to breast and ovarian cancer. The BRCA1 coding sequence disclosed in the priority document (P2) deviated from that disclosed in the application as filed by 15 nucleotide residues. The board recalled that the Enlarged Board of Appeal in G 2/98 (OJ 2001, 413) had rejected an extensive interpretation of the concept of "the same invention", which makes a distinction between technical features which are related to the function and effect of the invention and technical features which are not, with the possible consequence that a claimed invention is considered to remain the same even though a feature is modified or deleted, or a further feature is added. The case law of the boards dealing with the concept of "the same invention" in the field of biotechnology and especially in connection with inventions involving nucleotide sequences and amino acid sequences (T 351/01, T 30/02, T 70/05, T 923/92) had also taken a strict approach. The proprietor/appellant took the view that, if parameters (here: the nucleic acid sequence) which are used to define a substance (here: a nucleic acid) in a claim were known to vary within margins of commonly encountered experimental errors, the occurrence of variation in such a parameter between a disclosure in a priority document and the later application did not necessarily abrogate entitlement to the claimed priority. The need for legal certainty for third parties could not be higher than experimental certainty. The proprietor further argued that the technical problem underlying the patent in suit was the provision of the isolated BRCA1 gene as a tool to diagnose a predisposition to breast or ovarian cancer. The sequence deviations were irrelevant for solving this problem. However, the board rejected both approaches as not being compatible with the EBA's conclusion in G 2/98.
On the other hand, in two further decisions of Board 3.3.04, T 80/05 and T 666/05, it was held that certain sequence deviations between the patent in suit and the contested priority documents (P2 and P4, respectively) did not affect the invention claimed. Consequently, in both cases the corresponding priority date was found to be valid.
In T 250/06, claim 1 of the second auxiliary request related to recombinant DNA molecules comprising a nucleotide sequence encoding a murine delta opioid receptor (DOR), characterised as hybridising under conditions of low stringency to the DNA sequence shown in Figure 5. Appellant II pointed out that Figure 5 of the priority document differed by the addition of seven interspersed bases in the 3' untranslated region. The board indicated that conditions of low stringency were developed for screening molecules which differ somewhat from the probe. It was fully expected that the group of molecules obtained by hybridisation to the DNA of Figure 5 of the priority document and of the patent in suit respectively would not be different.