Cytology and mendelism: early connection between Michael F. Guyer's contribution

This paper examines the contribution of the PhD dissertation of the American cytologist Michael F. Guyer (1874-1959) to the early establishment (in 1902-1903) of the parallel relationship between cytological chromosome behaviour in meiosis and Mendel's laws. Guyer's suggestions were among the first, which attempted to relate the variation observed in the offspring in hybridisation studies by a coherent cytological chromosome mechanism to meiosis before the rediscovery of Mendel's principles. This suggested for the first time that the chromosome mechanism involved a conjugation of maternal and paternal chromosomes during the synapsis followed by a segregation of parental chromosomes in the final germ cells and a random union of the final germ cells in the fertilization. It shows that this early suggestion was similar to William Austin Cannon's later chromosome proposal attempting to explain Mendel's principles and had some influence on Walter Sutton's cytological suggestion explaining correctly the behaviour of Mendel's particle by 1903.