Sir

You report1 the legal decision in the long-running Roche–Promega dispute, that the US patent on full-length Taq DNA polymerase is invalid. The patent (4,889,818) had been awarded to Cetus Corporation and subsequently bought by Roche. This decision does not affect the validity or enforceability of Roche's foundational patents on polymerase chain reaction (PCR) and other related patents, including those for using any thermostable enzyme, including native Taq, for PCR.

I believe that the court's decision was wrong and unfair to Cetus scientists David Gelfand and Susanne Stoffel, in that it did not distinguish their invention from the work of the Gorodetskii2 and Trela3 groups. Cetus scientists including Gelfand and Stoffel were the first4 to isolate and clone the full-length (molecular mass 94,000; 94K) Taq DNA polymerase. The earlier groups repeatedly published their isolation of Taq fragments (60K–70K), undoubtedly the result of proteolytic degradation, under the mistaken impression that it was the complete enzyme.

Instead of concentrating on the validity of the Cetus invention, Promega's case was based on misrepresenting the raw experimental data of the scientists and their good-faith interpretations of it. By this stratagem, Promega is trying to rewrite history by asserting that Cetus had data indicating that the earlier groups isolated a 94K enzyme even when those laboratories' own publications show clearly and repeatedly that they did not. Readers can obtain these articles and judge for themselves who deserves credit for isolating and cloning the full-length Taq DNA polymerase.