Hugo Marie de Vries (1848-1935)
Hugo Marie de Vries was a Dutch botanist who independently rediscovered the laws of heredity developed by the Austrian monk Gregor Mendel and brought the concept of mutation into evolutionary theory.
Born in Haarlem on February 16, 1848, De Vries developed an early interest in botany. He received his Ph.D. from the University of Leiden in 1870, then went to the University of Heidelberg to work with the German plant physiologist Julius von Sachs. In 1877 he became a professor of botany at the University of Amsterdam, where he continued his research on the physiology of plant cells.
By the late 1880s De Vries had become interested in the growing controversy surrounding plant heredity, particularly with regard to evolutionary theory. His hybridization experiments led him in 1900 to rediscover Mendel's laws of heredity. De Vries, along with two other scientists who independently made the same rediscovery, gave full credit to Mendel's work when he became aware of it. De Vries, however, adhered to his own concept of heredity, published in 1899, in which he proposed that units called pangenes were the carriers of hereditary traits. Like Mendel's so-called factors, pangenes were theorized as discrete, independent units. Unlike Mendel's factors, they usually were considered to govern larger-scale hereditary traits. This viewpoint led De Vries to interpret his studies of the evening primrose in terms of what he called mutations: large-scale variations that could produce a new species in a single generation. According to De Vries, new species arose primarily in this manner, with no obvious transition forms. The enormous early popularity of this theory was due in part to its being seen as an alternative to Darwin's theory of natural selection, which emphasized the slow development of new species through almost imperceptible individual differences.
De Vries's formulation eventually had to be modified, and his research was shown to some extent to be in error. Nevertheless, his work is valued as the first satisfactory application of experimental methods to the traditionally speculative field of evolutionary theory. He died in Amsterdam on May 20, 1935.
Photo courtesy of http://www.nceas.ucsb.edu/~alroy/lefa/. Biography courtesy of Microsoft Encarta '97 Encyclopaedia.