Mendel counted traits in the offspring of crossed pea plants and proposed laws of inheritance. His nineteenth-century findings gained wider recognition only later.
He selected easily distinguishable traits and controlled pollination. Modern genetics explains the patterns through concepts such as genes, but not all of today's terminology existed at the time.
Early life and education
Mendel was born into a German-speaking family in Heinzendorf bei Odrau, in Silesia, Austrian Empire (now Hynčice in the Czech Republic). He was the son of Anton and Rosine (Schwirtlich) Mendel and had one older sister, Veronika, and one younger, Theresia. They lived and worked on a farm which had been owned by the Mendel family for at least 130 years (the house where Mendel was born is now a museum devoted to Mendel). During his childhood, Mendel worked as a gardener and studied beekeeping. As a young man, he attended gymnasium in Troppau (Czech: Opava). Due to illness, he had to take four months off during his gymnasium studies. From 1840 to 1843, he studied practical and theoretical philosophy and physics at the Philosophical Institute of the University of Olomouc (German: Olmütz), taking another year off because of illness.
Experiments on plant hybridization
Mendel, known as the "father of modern genetics," chose to study variation in plants in his monastery's 2 hectares (4.9 acres) experimental garden. Mendel was assisted in his experimental design by Aleksander Zawadzki while his superior abbot Napp wrote to discourage him, saying that the Bishop giggled when informed of the detailed genealogies of peas.
After initial experiments with pea plants, Mendel settled on studying seven traits that seemed to be inherited independently of other traits: seed shape, flower color, seed coat tint, pod shape, unripe pod color, flower location, and plant height. He first focused on seed shape, which was either angular or round. Between 1856 and 1863 Mendel cultivated and tested some 28,000 plants, the majority of which were pea plants (Pisum sativum). This study showed that, when true-breeding different varieties were crossed to each other (e.g., tall plants fertilized by short plants), in the second generation, one in four pea plants had purebred recessive traits, two out of four were hybrids, and one out of four were purebred dominant. His experiments led him to make two generalizations, the Law of Segregation and the Law of Independent Assortment, which later came to be known as Mendel's Laws of Inheritance.
Other experiments
Mendel also experimented with hawkweed (Hieracium). He published a report on his work with hawkweed, a group of plants of great interest to scientists at the time because of their diversity. However, the results of Mendel's inheritance study in hawkweeds were unlike those for peas; the first generation was very variable, and many of their offspring were identical to the maternal parent. In his correspondence with Carl Nägeli he discussed his results but was unable to explain them. It was not appreciated until the end of the nineteenth century that many hawkweed species were apomictic, producing most of their seeds through an asexual process.
Mendel appears to have kept animals at the monastery, breeding bees in custom-designed bee hives. None of his results on bees survived, except for a passing mention in the reports of the Moravian Apiculture Society. All that is known definitely is that he used Cyprian and Carniolan bees, which were particularly aggressive, to the annoyance of other monks and visitors of the monastery, such that he was asked to get rid of them. Mendel, on the other hand, was fond of his bees and referred to them as "my dearest little animals".
After his death, Mendel's colleagues remembered that he bred mice, crossing varieties of different sizes, although Mendel had left no record of any such work. A persistent myth has developed that Mendel turned his attention to plants only after Napp declared it unseemly for a celibate priest to closely observe rodent sex. In a 2022 biography, Daniel Fairbanks argued that Napp could hardly have given such a pronouncement, as Napp personally oversaw sheep breeding on the monastery's extensive agricultural estate.
Mendel also studied astronomy and meteorology, founding the 'Austrian Meteorological Society' in 1865. The majority of his published works were related to meteorology.