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Gregor Mendel (1822 - 1884), an Austrian monk, intitiated the modern study of heredity with his observations of the statistical distribution of offspring produced by the breeding of varieties of pea plant, such as dwarf and tall. Although not the first to study heredity, Mendel was the first to record his results in such detail that it was possible to see the significance of the proportions in which each type of individual arose. The only satisfactory explanation for the ratios of offspring types (phenotypes) which he observed was that heritable characteristics were particulate. Mendel postulated that ‘factors’ were responsible for the transmission of discrete features from parent to offspring. These factors were later termed genes and their transference between generations as discrete units enables both parents to contribute to the genetic make-up (genotype) of the offspring without blending of characteristics. Modern laws of heredity have their basis in Mendel\'s studies, which were published in 1865 but not recognized as important until 1900, when they were rediscovered by the Dutch geneticist Hugo de Vries. Since the beginning of the 20th century, genetics has played an increasingly pivotal role in biology and Mendel\'s original conclusions have been extensively modified, but his principles of heredity have endured. RB
See also blending inheritance; meiosis. |
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