Thomas Hant Morgan

Thomas Hant Morgan

American geneticist, Nobel laureate 1933
Date of Birth: 25.09.1866
Country: USA

  1. Biography of Thomas Hunt Morgan
  2. Morgan's Contributions to Genetics
  3. Major Works

Biography of Thomas Hunt Morgan

Thomas Hunt Morgan, an American geneticist and Nobel Laureate in 1933, was born into a diplomat's family. He graduated from the University of Kentucky, obtaining his bachelor's degree in 1886. After completing his studies, Morgan worked at the Johns Hopkins University. From 1888 to 1889, he conducted scientific research at the American Committee for Fisheries. In 1890, he received his doctorate from Johns Hopkins University and the same year, he was awarded the Adam Bruce Fellowship, which allowed him to travel to Europe and work at the Marine Biological Laboratory. It was there that he met Hans Driesch and Kurt Herbst, who influenced his interest in experimental embryology.

Thomas Hant Morgan

From 1904 to 1928, Morgan held the position of Professor of Experimental Zoology at Columbia University in New York. From 1928 to 1945, he served as a Professor of Biology and Director of the laboratory at the California Institute of Technology in Pasadena. In his later years, he acquired a small laboratory in Corona del Mar, California.

Morgan's Contributions to Genetics

In one of his early works, Morgan criticized Mendel's theory of inheritance. He believed that chromosomes were not carriers of heredity but rather products of early stages of development. He also disagreed with Darwin's notion of "gradual changes" and instead favored the idea of mutations proposed by Dutch botanist Hugo de Vries. During that time, little was known about the mechanism of inheritance, and the study of evolution and heredity relied on comparing the morphology and physiology of different species. Morgan's early research on inheritance followed this conventional approach. However, he soon turned to experiments in the hope of obtaining concrete results.

In 1897, while studying the regenerative abilities of certain organisms, Morgan published his first article on the phenomenon of regeneration, which contributes to the successful survival of a species. In 1900, Gregor Mendel's works on the inheritance of traits in peas captured the attention of geneticists worldwide. It was during this time that biologist W. Sutton proposed that units of inheritance (genes) were located within or on the surface of cellular structures called chromosomes. Morgan disagreed with this, maintaining that chromosomes were products of early stages of organism development.

In 1909, Morgan began working with the fruit fly Drosophila as a model organism. It had only four pairs of chromosomes, started reproducing two weeks after birth, and produced offspring in quantities of around 1,000 individuals after 12 days. Other researchers, such as C. W. Woodworth and F. E. Lutz, had also studied Drosophila for genetic research, and Lutz introduced Morgan to the results of his work, as Morgan was searching for a more affordable model organism for his own scientific investigations.

Very soon, in 1909, the first mutations appeared in Morgan's experiments with Drosophila. The subsequent study of this phenomenon ultimately allowed Morgan to determine the exact location of genes and understand their principles of operation. One of the most significant discoveries was the observation of the "linkage" of certain genes to sex. Morgan referred to this phenomenon as the "linkage" of genes, as he found that white eyes in fruit flies were only passed down to male individuals. Analyzing a vast amount of data, Morgan came to interesting conclusions. Genes located on the same chromosome were less likely to be inherited together than expected. This indicated the possibility of chromosome breakage and the exchange of genetic material between chromosomes. Morgan and his colleagues created "maps" of Drosophila chromosomes based on this concept. His hypothesis of the "linear" arrangement of genes on chromosomes and the dependence of gene linkage on their distance from each other was a revolutionary discovery in genetics.

In 1919, Morgan was elected as a Foreign Member of the Royal Society in London, and in 1924, he was awarded the Darwin Medal. In 1933, he received the Nobel Prize for his discoveries related to the functions of chromosomes in the transmission of hereditary traits.

Major Works

- Regeneration. N-Y: Macmillan, 1901.
- Heredity and Sex. N-Y: Columbia Univ. Press, 1913.
- The Theory of the Gene. New Haven, CT: Yale Univ. Press, 1932.
- The Scientific Basis of Evolution. London: Faber and Faber, 1932.