DeVries, Correns, and Tschermak.
Honors Post-AP Advanced Topics in Biology
December 11, 2003
DeVries, Correns, and Tschermak
Three botanists, Hugo De Vries, Carl Erich Correns, and Erich Von Tschermark-Seysenegg, made possible for the spread and understanding of Mendel’s work that has led to the modern understanding of the gene today. They re-discovered Mendel’s laws in 1900 by independently working on plant hybrids. Their discoveries paved the way for the connection between Mendelian genetics and medicine, which was instigated by Archibald Garrod. This was complimented by greater discoveries in genetics, especially by Thomas Hunt Morgan, Herman J Muller, George Beadle, and Edward Tatum.
Hugo de Vries (1848-1935) worked at the University of Amsterdam in 1880, as a professor of botany. Simultaneously, he worked on a series of genetic hybridization experiments. Working with the Oenothera lamarckiana (the evening primrose), de Vries was able to produce his theory of mutation. He agreed with discontinuous variation, staging that species evolve from other species by large sudden phenotypic changes. In his case, he noticed that a plant would usually have offspring that contained noteworthy differences from it such as leaf shape or plant size. These offspring would then occasionally pass these traits to their offspring. Ignoring that these traits observed in the primrose usually were from aberrant chromosomal segregations and not mutation, de Vries certainly had the right idea. Although he did not know of Mendel’s work, when he published his work in 1990, he concluded with identical results. When he first published his work in French, it did not credit Mendel; however, this was later amended in his German publication.
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In Munich Germany, Carl Erich Correns (1864-1933) entered the University of Munich in 1885. With the help of Nageli, Correns interests in botany and the study of genetic traits grew. From Nageli, Correns knew about Mendel’s hawkweed plant experiments; however, he never learned of Mendel’s principal pea plant experiments. By 1990; however, he became aware of Mendel’s conclusions and acknowledged Mendel in the publishing of his work, G. Mendel’s Law Concerning the Behavior the Progeny of Racial Hybrids. In contrast to de Vriens, Correns was a strong believer that credit should be given where it is deserved. Most notably, Correns restated Mendel’s Law of Independent assortment, implying that in the production of sex cells, a segregation of factors occurs.
Erich von Tschermak came from a distinguished family of botanists; his grandfather was known to have taught Mendel. Similarly to Mendel, he used peas in his plant breeding experiments in 1898. His hybridization experiments aimed to improve crops, and he did produce crops such as wheat, barley, and oats. Consequently, he became a professor at the University of Agricultural Studies in Vienna. Tschermak was vexed about the acceptance of his paper among those of de Vries, Correns, and Mendel, because he was younger. However, he claimed his due credit on the reestablishment of Mendel’s laws.
Mendel’s work included explanations on how traits are inherited, how mutations affect traits, and the mapping of genes on chromosomes. Although this was highly important and useful information, it was not very influential at first. Among the top biologists, Mendel’s information was often known; however, the more it trickled down to other scientists, the less recognized it became. By independently reaching the same conclusions as Mendel, Correns, de Vries, and Tschermak re-discovered his paper and allowed for a flow of Mendelian genetics into scientific circles. They put an emphasis on the importance of Mendel’s work, added credibility to his research, and helped enforced the idea that a gene is a physical object. Their rediscovery played a vital role, as it helped begin a revolution in genetics. De Vries, Tschermak, and Correns paved the way for Walter Sutton, who followed them in 1902. Sutton pointed out interrelationships between cytology and Mendelism. He related the structure of a cell to heredity. By using the theory of segregation, Sutton understood that hereditary factors lie on chromosomes. In 1908, with the foundation of de Vries’s theory of mutation, Archibald Garrod proposed that the lack of a certain enzyme could cause certain human diseases, which could then be passed onto offspring. He was the first to discover a disease, alkaptonuria, that matched Mendel’s theories. Much later, in 1941, Beadle and Tatum proved that genes produce their effects by regulating specific enzymes. Continuing to build off of the theory of mutation and independent assortment, Thomas Hunt Morgan discovered sex-linked inheritance from a fruit fly. His evidence was found in a certain fruit fly that had a white-eye mutation. Muller than used x-rays to cause mutations in fruit flies in 1927. This culminated in the theory of linkage as well as the gene theory.
Correns, de Vries, and Tschermak all independently rediscovered Mendel’s theories and enforced their importance. With their help, Mendel’s theories have shaped modern genetics and medicine. New scientists stood on their shoulders to creative innovative discoveries in modern biology today.