Thomas Hunt Morgan

Morgan was born and raised in Kentucky, and received his bachelor's degree from the State College of Kentucky in 1886. He pursued graduate study at Thomas Hunt Morgan won the 1933 Nobel Prize in physiology or medicine for his discoveries concerning the role of chromosomes in heredity. Johns Hopkins University in Baltimore, and eventually became a professor of biology at Bryn Mawr College in 1891. His early interests were in developmental biology and evolution. After moving to Columbia University in 1901 and coming under the influence of the great cell biologist Edwin Wilson, Morgan turned his attention to understanding the physical basis of inheritance, which he saw as a means to test theories about the role of mutation in evolution.

At the time Morgan began his work, chromosomes had been seen in cells, but their significance was unknown and not widely considered. A student of Wilson's, Walter Sutton, had recently proposed that chromosomes carried the genetic material, but had little evidence to support this important hypothesis. At the time, the gene itself was an abstract concept with no known physical correlate, and many scientists thought it was not a physical entity at all, but only a convenient fiction for describing some experimental results. In fact, it was Morgan's use of the term "gene" that helped bring it into general use in science.

To attack the issue of heredity, Morgan chose to work with the fruit fly, Drosophila melanogaster. This fly requires little space, breeds quickly, has many observable characteristics, and has only four chromosomes, making it an ideal model organism for genetics studies. Morgan also gathered a trio of very bright students, Hermann Muller, Alfred Sturtevant, and Calvin Bridges, and cultivated an egalitarian system of collaboration that was unknown in most other labs. The combination of the right question, the right model, the right collaborators, and some luck allowed Morgan and his group in their lab, dubbed "The Fly Room," to make their fundamental discoveries. Beginning in 1908, they proved that chromosomes do indeed carry the genes, that genes are discrete physical things arranged on chromosomes like beads on a string, that genes change places on chromosomes, that genes can be mutated and those mutations are faithfully inherited, and that mutations can be caused by exposure to high-energy radiation or other environmental phenomena.