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MENDEL, Gregor (1822-84). The laws of heredity on which the modern science of genetics is based were discovered by an obscure Austrian monk named Gregor Mendel. Yet Mendel's discoveries remained virtually unknown for more than 30 years after he completed his experiments--in spite of the fact that his papers reached the largest libraries of Europe and the United States. (See also Genetics; Heredity.)

Johann Mendel was born on July 22, 1822, in Heinzendorf, Austria. He took the name Gregor when he entered the monastery in Brunn, Moravia (now Brno, Czech Republic) in 1843. He studied for two years at the Philosophical Institute in Olmutz (now Olomouc, Czech Republic), before going to Brunn. He became a priest in 1847. For most of the next 20 years he taught at a nearby high school, except for two years of study at the University of Vienna (1851-53). In 1868 Mendel was elected abbot of the monastery.

Mendel's famous garden-pea experiments began in 1856 in the monastery garden. He proposed that the existence of characteristics such as blossom color is due to the occurrence of paired elementary units of heredity, now known as genes. Mendel presented his work to the local Natural Science Society in 1865 in a paper entitled "Experiments with Plant Hybrids." Administrative duties after 1868 kept him too busy for further research. He lived out his life in relative obscurity, dying on Jan. 6, 1884. In 1900, independent research by other scientists confirmed Mendel's results.


From Compton's Interactive Encyclopedia © 1998 The Learning Company, Inc.


Gregor Mendel

The first person to discover the basic laws of heredity and suggest the existence of genes was an Austrian monk, Gregor Mendel, b. July 22, 1822, d. Jan. 6, 1884. The importance of his work was not realised until 1900, at which time his findings laid the foundation for the science of genetics.

Born Johann Mendel in Heinzendorf, Austrian Silesia (now Hyn°ice, Czech Republic), he changed his name to Gregor in 1843 when he entered the Augustinian monastery at BrŸnn (now Brno). He was ordained a priest in 1847 and in 1851 was sent to the University of Vienna for training as a teacher of mathematics and natural sciences. He returned to BrŸnn in 1854, where he taught until 1868.

In a monastery garden Mendel began (1856) the breeding experiments that led him to discover the laws of heredity. Working with garden peas, he studied seven characteristics that occur in alternative forms: plant height (tallness vs. shortness), seed colour (green vs. yellow), seed shape (smooth vs. wrinkled), seed-coat colour (gray vs. white), pod shape (full vs. constricted), pod colour (green vs. yellow), and flower distribution (along length vs. at end of stem). Mendel made hundreds of crosses by means of artificial pollination. He kept careful records of the plants that were crossed and of the offspring. In 1865, Mendel reported his findings at a meeting of the BrŸnn Natural History Society. The following year his results were published as "Experiments with Plant Hybrids" in the society's journal.

Mendel summarised his findings in three theories. He asserted that during the formation of the sex cellsÑthe egg and the spermÑpaired factors segregated, or separated. Thus a sperm or egg may contain either a tallness factor or a shortness factor, not both. This theory is called Mendel's first law, or the principle of segregation.

Mendel's second law, called the principle of independent assortment, stated that characteristics are inherited independently of one another. That is, the tallness factor may be inherited with any other factor, dominant or recessive. This law later was modified when Thomas Hunt Morgan discovered linkage, or the inheritance of two or more genes situated close to each other on the same chromosome.

The third theory stated that each inherited characteristic is determined by the interaction of two hereditary factors (now called genes), one from each parent. In the characteristics that he studied, Mendel found that one factor of the pair always predominated over the other. For example, tallness was always dominant over shortness. This theory became known as the law of dominance.

With his promotion to abbot of the monastery in 1868, Mendel gave up his experiments. Although respected by his fellow monks as well as by his students, Mendel, at the time of his death, was still not recognised as a great scientist. Sixteen years later, three European scientists - Hugo De Vries, Carl Correns, and Erich Tschermak von Seysenegg - working independently discovered Mendel's writings as they were conducting experiments similar to his and credited him as the discoverer of the laws of heredity.

Reviewed by Louis Levine

Bibliography: Bowler, P. J., Mendelian Revolution (1989); Corcos, A. F., and Monaghan, F. V., Gregor Mendel's Experiments on Plant Hybrids (1993); Iltis, Hugo, Life of Mendel, trans. by Eden and Cedar Paul (1932; repr. 1966); Olby, Robert C., The Origins of Mendelism, 2d ed. (1985); Orel, V’t¹zslav, Gregor Mendel: The First Geneticist, trans. by S. Finn (1996).

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