Contributions to Zoology, 86 (4) – 2017Jacques J. M. van Alphen; Jan W. Arntzen: The case of the midwife toad revisited

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The results that Kammerer claims to have obtained by forcing midwife toads to breed in water are difficult to explain with current biological knowledge. Selection in his experiments by the raised temperature could not have produced the simultaneous changes in so many traits. The numbers of animals used and the number of generations his experiments lasted are not sufficient to obtain such results. Invoking epigenetics to explain the results requires that a large number of genes, distributed over different chromosomes would all have to be silenced or switched-on simultaneously. Even if one assumes that all the genes involved are selectively (in)activated in one of the sexes, then Vargas et al. (2016) would still have to provide a selective advantage for the gradual increase in expression of the acquired characters with subsequent reproductive cycles and generations. Hence, we do not see how the genetic architecture proposed by Vargas et al. (2016) to explain Kammerer’s data could have evolved.

Vargas et al. (2016) conclude that “In the light of modern scientific knowledge, we can confidently state that Kammerer’s experiments do not contain any phenomenon that cannot be explained by currently known experiments and epigenetic mechanisms”. We could not disagree more and we see no way in which modern science could possibly explain Kammerer’s claims for the inheritance of acquired characteristics. We show, through careful examination, that there is no other than one consistent manner to explain his results and that is that they have been cooked, that is, fabricated to support his theory of evolution by acquired characters, in the midwife toad as well as in the other amphibian species Kammerer worked with (van Alphen & Arntzen, 2016). We consider the reported data discrepancies to be the final nail in his coffin. To hail Paul Kammerer as an academic forbearer is a mistake the epigenetics research community might wish to avoid.