In T 250/06 the board emphasised that, for priority to be acknowledged, it was not sufficient that a formal support for the claimed subject-matter be found in the priority document; on the contrary, it pre-supposed that the priority document also provided an adequate technical teaching in respect of said subject-matter and that this was the "same" teaching as that of the European patent.
Claim 1 related to a group of recombinant DNA molecules comprising a nucleotide sequence encoding a vertebrate delta opioid receptor (DOR) characterised as hybridising under conditions of low stringency to the mouse DOR DNA sequence shown in Figure 5. The priority document taught the cloning of the mouse DOR DNA and its sequence. According to the board, it was readily apparent from the priority document that its teaching on its own was not sufficient. In Example 6, a human DOR DNA was allegedly identified by probing a human DNA library with mouse DOR DNA. Yet, the clone so isolated turned out to be μOR DNA. The European application disclosed the isolation of μ, κ and DOR clones and their unambiguous characterisation, in particular by comparison with sequences then available in the art. Thus, it contained a technical teaching different from (more complete than) that of the priority document.
In T 1443/05, too, the board concluded that the teaching of the contested patent, which included a disclaimer not present in the previous European application from which priority had been claimed, was different from the teaching of the latter, such that the requirement of the "same invention" according to Art. 87(1) EPC and G 2/98 (OJ 2001, 413) was not met. The board also found in this case that examples included in the previous application (now an Art. 54(3) EPC 1973 document) anticipated the subject-matter of claim 1 of the patent in suit (in this respect see also T 680/08).