Armin von Tschermak-Seysenegg (1870–1952): Physiologist and Co-‘Rediscoverer’ of Mendel’s laws

Abstract

The 'rediscovery' of Mendel's laws in 1900 was a turning point in modern research of heredity/genetics. According to the traditional view, adopted and fostered by many textbooks of genetics, Mendel's principles were presented in the first half of 1900 simultaneously and independently by three biologists (H. de Vries, C. Correns, E. v. Tschermak-Seysenegg). Having thus laid the foundations of further development, the 'rediscovery' continues to attract considerable interest. Since the 1950s, however, serious questions arose concerning both the chronology and specific conceptual achievement of the scientists involved. Not only the independence but also parallelism was analysed in the context of individual research programmes of these three scholars. The youngest of them, Erich v. Tschermak-Seysenegg, was even excluded from the list of 'rediscoverers'. The aim of this paper is to use new archival evidence and approximate the contribution of the physiologist and ophthalmologist Armin von Tschermak-Seysenegg (1870-1952) to the events of 1900 and 1901.

Inheritance of seed size by hybrid populations of pea (F1, F2)

“…The ratio of the number of small type of seeds to the number of other types of seeds was 1:264 and it was close to 1:255, corresponding to the tetrahybrid segregation. Tschermak drew conclusion that the small-seeded sample which he had used in the crosses carried 4 recessive genes of seed size, which he denominated as a, b, c, d, while large-seeded sample had dominant alleles -A, B, C, D [14][15][16].…”