In T 923/92 (OJ 1996, 564) 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 G 2/98 (OJ 2001, 413), 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. See also decision T 1213/05.

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 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.