Heredity particulate inheritance of genes can be attributed to the Moravian monk Gregor Mendel who published his work on pea plants in 1865. However, his work was not widely known and was rediscovered in 1901. It was initially assumed that Mendelian inheritance only accounted for large (qualitative) differences, such as those seen by Mendel in his pea plants—and the idea of additive effect of (quantitative) genes was not realised until R. A. Fisher's (1918) paper, "The Correlation Between Relatives on the Supposition of Mendelian Inheritance" Mendel's overall contribution gave scientists a useful overview that traits were inheritable. His pea plant demonstration
Franz Unger of botany at the University of Graz and also taught at the Joanneum (which became the Universalmuseum Joanneum and the Graz University of Technology); in 1850 professor of plant physiology in Vienna. In 1852 he travelled to Northern Europe and to the Orient. Unger retired in 1866 and lived on his farm near Graz. Unger was one of the major contributors to the field of paleontology, later turning to plant physiology and phytotomy. He hypothesized that (then unknown) combinations of simple elements inside a plant cell determine plant heredity and greatly influenced the experiments of his student Gregor Johann Mendel.