Gregor Mendel

Austrian geneticist

• Born: July 22, 1822
• Birthplace: Heinzendorf, Austria (now Hyncice, Czech Republic)
• Died: January 6, 1884
• Place of death: Brünn, Austro-Hungarian Empire (now Brno, Czech Republic)

Mendel’s work was almost unknown during his lifetime, and he died without receiving any significant recognition. However, he demonstrated the rules governing genetic inheritance with a novel statistical approach to experiments in plant hybridization, and after his work was recognized, his ideas transformed the field of genetics.

Early Life

Gregor Johann Mendel (MEHN-dehl) was the only son of Anton Mendel, a peasant, and his mother was the daughter of a village gardener. He had four sisters, two of whom died early, but Veronica, born in 1820, and Theresia, born in 1829, survived. The Mendel lineage included other professional gardeners. Fortunately for his future career, Mendel went to a village school where the teacher taught the children about natural science. Mendel was exposed early to the cultivation of fruit trees, at the school as well as at home, where he helped his father with the family orchard. Mendel attended secondary school in the year 1833 and then spent six years in the gymnasium in Troppau, where he did well overall.

Mendel’s nervous physical reaction to stress, which partially determined Mendel’s choices and possibilities in later life, became evident when he was a student. Initially, when Mendel’s father, unable to work because of serious injuries, had to give his son-in-law control of the farm in 1838, Mendel gave private lessons to make money. The stress affected him to such a degree that he had to miss several months of his fifth year at the gymnasium in order to recover.

Mendel started a philosophy course at the Philosophical Institute at Olmütz in 1840 but was unable to find tutoring jobs. He fell ill again and spent a year with his parents. His sister Theresia offered to support him out of her dowry so he could continue his studies. With her aid, Mendel completed the two-year course in philosophy, physics, and mathematics, which would have led to higher studies. He did well enough that one of his professors, who had lived in an Augustinian monastery for nearly twenty years, recommended Mendel to the same monastery.

Life’s Work

Mendel entered the Augustinian monastery, taking the name Gregor, on October 9, 1843, out of sheer financial necessity. It proved, however, to be a fruitful decision. Though he felt no great vocation to be a monk, he found himself in the environment most conducive to his studies; it was at the monastery that Mendel was able to concentrate on those studies in meteorology and, more significant, plant reproduction that made him a pioneer in genetics .

The abbot of the monastery was actively involved in encouraging agricultural studies, so Mendel was surrounded by other scholars and researchers. The nervous disposition that had affected him as a student continued to plague him, for he would become ill when he visited invalids. Useless as a pastor, he was assigned instead to the gymnasium in Znaim as a substitute teacher. In this capacity, Mendel was successful and was encouraged to become a teacher permanently, if he could pass the required examinations for a license.

Ironically, this careful researcher never made much headway in official academic circles, though his education was crucial to shaping the course of his experiments. He failed to pass all the examinations to become a permanent teacher and was sent to the University of Vienna to study natural science more thoroughly. From October, 1851, to August, 1853, Mendel was in the intellectually stimulating company of men such as Franz Unger, a professor of plant physiology, who asserted that the plant world was not fixed but had evolved gradually—a view that caused much controversy.

From Christian Doppler and Andreas von Ettingshausen, both physicists, Mendel most likely acquired the technique of approaching physical problems with mathematical analysis. He served as a demonstrator at the Physical Institute in Vienna and became adept at the physicist’s approach to a problem. In 1855, Mendel took the teachers’ examination again but fared even worse; he became sick after writing the first answer and was apparently so ill subsequently that his father and uncle came a long way to visit him. Because he never tried the examinations again, Mendel remained a substitute teacher for sixteen years, kind, conscientious, and well liked.

In 1856, he began his experiments with garden peas. It was known at the time that the first generation reproduced from hybrids tended to be uniform but that the second generation reverted to the characteristics of the two original plants that had been crossbred. Such facts were observable, but the explanations remained unsatisfactory. In An Introduction to Genetic Analysis (1976, 1981) the authors note that before Mendel, the concept of blending inheritance predominated; that is, it was assumed that offspring were typically similar to the parents because the essences of the parents were contained in the spermatozoon and the egg, and these were blended at conception to form the new offspring. Mendel’s work with pea plants suggested another theory, that of particulate inheritance; this theory postulated that a gene passes from one generation to the next as a unit, without any blending.

As several historians of science have noted, Mendel approached this problem of heredity in hybrids as a physicist would, and this may account for some of the suspicion surrounding the success of Mendel’s famous experiments with garden peas. Instead of making many observations of natural life and then looking for the general pattern, as was the conventional approach of biologists, Mendel determined the problem first, devised a solution to the problem, then undertook experiments to test the solution. Mendel prepared the groundwork for his experiments by testing thirty-four varieties of peas to find the most suitable varieties for research. From these, he picked twenty-two to examine for two different traits, color and texture. He was then able to trace the appearance of green and yellow seeds, as well as round and wrinkled ones, in several generations of offspring. By literally counting the results of his hybridization, he found the ratio of dominant genes to recessive ones: 3 to 1. In effect, he demonstrated that there was a rule governing inheritance.

When he finished his experiments with peas in 1863, Mendel was well aware that his conclusions were not what the scientific knowledge of the time would have predicted. To confirm his findings, he experimented with the French bean and the bush bean, crossed the bush bean with the scarlet runner, and got the same 3:1 ratio, though in the last case, he could not obtain the same ratio for the white and red colors. He spoke about his work at two meetings of the Naturforschenden Verein (natural science society) and was asked to publish his lecture in 1866. Only a few of the forty copies made have been recovered: One of the most important recipients was Carl von Nägeli, a leading botanical researcher who had written about the work of preceding experimenters. Nägeli found it impossible to accept Mendel’s explanation but did engage in discussion with him; the two corresponded from 1866 to 1873. Nägeli’s influence was not altogether salutary, for he set Mendel on a futile track experimenting with Hieracium, which, as was established later, breeds slightly differently.

In 1868, Mendel was promoted to abbot of the monastery. He became involved in a controversy about taxes on the monastery and eventually, in 1871, abandoned his studies of hybrids. A heavy smoker toward the end of his life, Mendel developed kidney problems, which led to a painful illness. Theresia, the sister who had helped him pay for his education with her dowry, was also there for his last days, taking care of him until he died in January of 1884.

Significance

Gregor Johann Mendel’s work was not rediscovered for thirty years, by which time three other researchers—Hugo de Vries, Carl Erich Correns, and Erich Tschermak von Seysenegg—had, working independently, drawn some of the same conclusions. Thus, Mendel’s work in itself did not directly influence the history of science, for it was not well known. Even his original explanations of meteorologic phenomena, particularly of a tornado that struck his birthplace, Brno, in 1870, was ignored. He died without achieving the full recognition he deserved.

The explanation for his contemporaries’ lack of appreciation for his work can only be speculative. For example, Mendel’s successor destroyed his private papers; furthermore, scientists at the time considered Mendel’s experiments to be a hobby and his theories the “maunderings of a charming putterer.” In part, Mendel’s use of numerical analysis, so different from the conventional working procedures of biologists up to that time, may have been suspect. Mendel’s personal qualities, which enabled him to reduce a puzzling problem to its bare essentials, may also have been a contributing factor to his obscurity. Though widely read in scientific literature and an active participant in the affairs of his community, he was a modest and reticent man, who compressed twenty years of scientific work into four short papers.

This lack of fanfare concerning his discoveries was not rectified until a young priest discovered Mendel’s official documents, preserved in monastery archives, in the first decade of the twentieth century. Only then were Mendel’s conscientious, careful, painstaking work and the results that he achieved fully appreciated. As L. C. Dunn notes, there had been several experiments with hybridization before Mendel. Among his predecessors, Josef Gottlieb Kölreuter was an important figure, for it was he who produced the first plant hybrid with a planned experiment in 1760.

What Mendel did that no one else thought to do was to apply statistical analysis to an area of study that had not habitually conceptualized problems numerically. By so doing, he was able to discover specific and regular ratios. With this apparently simple technique, Mendel was able to formulate the rules of inheritance and thus give birth to the science of genetics.

Bibliography

Dunn, L. C. A Short History of Genetics: The Development of Some of the Main Lines of Thought, 1864-1939. New York: McGraw-Hill, 1965. As indicated in the subtitle, this is a study of the development of the main lines of thought in genetic studies from 1864 to 1939. Contains chapters on Mendel and on the aftermath of Mendelism. Includes photographs, a glossary, a bibliography, and an index.

Henig, Robin Marantz. The Monk in the Garden: The Lost and Found Genius of Gregor Mendel, the Father of Genetics. Boston: Houghton Mifflin, 2000. Biography of Mendel, recounting his life, experiments, and the importance of his genetic discoveries. Includes bibliography, notes, and index.

Iltis, Hugo. Life of Mendel. Translated by Eden Paul and Cedar Paul. London: Allen & Unwin, 1932. Researched and written by the man who helped to rediscover Mendel and preserve his remaining papers. One of the best biographies of Mendel. Includes illustrations, color plates, and an index.

Mendel, Gregor. Experiments in Plant-Hybridisation. Foreword by Paul C. Mangelsdorf. Cambridge, Mass.: Harvard University Press, 1965. Reprinted to celebrate the centennial of Mendel’s lectures on his groundbreaking experiments. The foreword contains a concise explanation of the experiments and their significance.

Olby, Robert C. Origins of Mendelism. New York: Schocken Books, 1966. Places Mendel’s work in the context of those who came before him. Starts with Kölreuter and his hybridization experiments, includes a discussion of Charles Darwin’s genetics, and concludes with the work of the three who replicated Mendel’s work independently. Contains an appendix, an index, plates, and suggested readings at the end of each chapter.

Orel, Vítězslav. Gregor Mendel: The First Geneticist. Translated by Stephen Finn. New York: Oxford University Press, 1996. An account of Mendel’s life and activities as a scientist and a monk. Describes how his genetic ideas were received by his contemporaries and in the years following his discoveries.

Sturtevant, Alfred H. A History of Genetics. New York: Harper & Row, 1965. Provides a historical background of genetics from before Mendel through the genetics of mankind. Lively discussion of the controversy over Mendel’s near-perfect results. Includes a chronology of genetics history, a bibliography, and an index.

Suzuki, David T., Anthony J. F. Griffiths, and Richard C. Lewontin. An Introduction to Genetic Analysis. 2d ed. San Francisco: W. H. Freeman, 1981. A chapter on Mendelism provides a clear explanation of Mendel’s experiments, using contemporary terminology. Includes problems, with answers, a glossary, a bibliography, and an index.