The BSHS is delighted to announce the release of the second in our Translations series. Nils Roll-Hansen’s translation of Wilhelm Johannsen’s ‘About Darwinism, seen from the point of view of the science of heredity’ is now freely available on our website.

Wilhelm Johannsen is a standard reference in the history of genetics. He clarified the distinction between genotype and phenotype, and introduced the term ‘gene’. He also carried out the famous experiment of selection within pure lines of beans, an experiment that became a paradigmatic demonstration of the stability of genotype. Arguably Johannsen’s experimental and theoretical development of the distinction between the phenotype — which depends on variation in environment, — and the genotype — which remains stable through generations, — provided the basis for genetics as an exact science, experimentally and theoretically.

Johannsen’s magisterial treatise Elemente der exakten Erblichkeitslehre [Introduction to an exact science of heredity] profoundly influenced the development of genetics in the early decades of the 20th century. The original publication of 1909 was followed by thoroughly revised editions in 1914 and 1926. Johannsen published only a couple of relatively short and specialized genetics papers in English (in particular, Johannsen 1907, 1911, 1923). The popular 1903 article on Darwinism and heredity that is translated below gives an insight into the background and context of his developing theory of genotype. The article was written the same year that he published his classical bean selection experiment (Johannsen 1903), and shows how Johannsen at that point related his ideas about heredity to running debates on evolution, systematics and plant breeding

– Nils Roll-Hansen

Image copyright: the Royal Library, Copenhagen