Dutch plant physiologist. In 1900 he rediscovered Mendel's laws of inheritance, at the same time that Carl Correns did so independently. In 1889 De Vries had hypothesized the existence of "pangenes" (now called "genes") and argued for a saltationist mechanism of evolution, with selection only operating to produce local varieties. He believed that mutations could be induced simultaneously in multiple individuals by periods of stress in the environment, leading to the nearly instantaneous production of new species. He thought the main cause of evolutionary progression was "selection between species" in which unfit species were weeded out by extinction. Most of his research involved crossbreeding experiments on the evening primrose (Oenothera lamarckiana). Later it was shown that the "species" was a hybrid and the dramatic "mutations" were due to recombination of existing alleles (although many true mutations were found soon afterwards by other workers studying such organisms as rats and Drosophila flies). De Vries conducted lecture tours of the U.S. in 1904 and 1906. De Vries' views strongly influenced Bateson and many American experimental biologists like Morgan.
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