Mendel on violet spotting in his Pisum note
Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen Series C Biological & Medical Sciences 89(2): 203-216
In 1969 Heimans offered an analysis of Mendel's Pisum note in which he concluded that Mendel conceived compound characters which could remain constant upon self fertilisation but would segregate when hybridised with a different character. In this posthumously edited analysis of Mendel's explanation of the appearance and disappearance of violet spots in the successive generations of Pisum hybrids, Heimans appears to have brought his analysis of the Pisum note to a highly unexpected climax: the partial factors entering the compound in the parent appear not only to segregate upon hybridisation but also to have acquired different potentials in the offspring of the hybrids. Heimans concludes that Mendel did conceive here a new and essentially different hereditary mechanism as compared to his published views on variable and constant hybrids.