Darwin and Mendel on Inherited Variability

Darwin’s Origin of Species took many years of compilations and it was even accelerated by Alfred R. Wallace paper on the same subject in 1858. Origin of Species was really groundbreaking, because Darwin not only proposed common ancestry – that was in the air since Humboldt and Lamarck, and “Vestiges of the Natural History of Creation” -, but he proposed also a process for the underlying mechanism of the diversity of species.

His theory of evolution had 2 principles: common ancestry and natural selection. Natural selection can be described with 5 words: Variation, Inheritance, Selection, Time, Adaptation. Inherited variability and a selection pressure to adapt to the environment.

In Darwin’s time, the source of inherited variability was unknown. Darwin considered heredity as a “blending” process and the offspring were seen as essentially a “dilution” of the different parental characteristics.

Gregor Mendel – the Father of Genetics

On 6 January 1884, Gregor Mendel (1822-1884) passed away in Brünn, Czech Republic.

The title “Father of Genetics” can be attributed to Gregor Mendel in two capacities: he laid the groundwork for the new discipline of Genetics and he was an ordained priest and Augustinian friar – therefore, he was called “Father”, like all priests. 

Gregor Johann Mendel was born in Hyncice, Moravia on 20 July 1822 in what is now the Czech Republic. The only son of a peasant farmer, Mendel attended local schools and the Philosophic Institute at Olomouc. In 1843, he entered the Augustinian Order at St. Thomas Monastery in Brno (German: Brünn) and began his theological studies at the Brünn Theological College. He was ordained to the priesthood on 6 August 1847.

The Augustinians had been established in Moravia since 1350, and St. Thomas Monastery was a center of creative interest in the sciences and culture. Its members included well-known philosophers, a musicologist, mathematicians, mineralogists and botanists who were heavily engaged in scientific research and teaching. The library contained precious manuscripts and incunabula, as well as textbooks dealing with problems in the natural sciences. The monastery also held a mineralogical collection, an experimental botanical garden and a herbarium. It was in this atmosphere, Mendel later wrote, that his preference for the natural sciences was developed.

After his ordination, Mendel was assigned to pastoral duties, but it soon became apparent that he was more suited to teaching. In 1849, he was assigned to a secondary school in the city of Znaim, where he was well received by his students. However, when he took the qualifying state examination for teacher certification, he failed. Recognizing that Mendel was largely self-taught, one of his examiners recommended that he be sent for further studies in the natural sciences. The abbot agreed, and Mendel was sent to the University of Vienna in order to improve his preparation for the reexamination. Mendel spent two years in Vienna (1851- 1853), where he attended lectures and seminars in the natural sciences and mathematics. It was there that he acquired the empirical, methodological and scientific research skills which he was to apply to his later investigations. Mendel returned to teaching in Brünn in 1854 but when, two years later, he again attempted the state certification examination he became ill, most likely as a result of debilitating test anxiety, and withdrew. He did not pursue the examination further but returned to Brünn in 1856 where he continued to teach part-time.