The Criticisms of Pangenesis: The Years of Controversy.

When first published in 1868, Darwin's Pangenesis was almost uniformly rejected by his contemporaries. Until recently it has still been regarded as Darwin's biggest mistake or a brilliant blunder. There are three main reasons for this. First, Galton transfused the blood of one variety of rabbit into another, and then bred together the latter. The results of breeding showed no variations of characters in the offspring. Thus he concluded that Darwin's Pangenesis was incorrect. Second, there was no direct evidence for the existence of Darwin's imaginary gemmules. Third, Darwin's Pangenesis explained the Lamarckian inheritance of acquired characters, graft hybridization, xenia and telegony, which were largely thought to be doubtful phenomena. Now the discoveries of circulating cell-free DNA, mobile RNAs, prions and extracellular vesicles provide striking evidence for the chemical existence of Darwin's supposed gemmules. There is also convincing evidence for heritable changes induced by blood transfusion in which Galton failed to find such effects in his experiment. Moreover, there is increasing evidence for the inheritance of acquired characters, graft hybridization, xenia and other phenomena that Pangenesis was designed to explain. In light of the mounting evidence, it is not proper to continue to consider Pangenesis as Darwin's biggest mistake or a brilliant blunder.