Thomas Hunt Morgan

Thomas Hunt Morgan (born September 25, 1866, died December 4, 1945) was awarded the 1933 Nobel Prize in Physiology or Medicine for his work in genetics, specifically his discoveries in the role of the chromosome in heredity.

Morgan, embryologist and geneticist, provided the final piece of the puzzle that made genetics a science based in experimental evidence drawn from supporting data.

Gregor Johann Mendel working in the 19th century had noted general concepts of inheritance, that life forms produced progeny that carried parental characteristics. Mendel, however, was not able to show the mechanisms that made it possible for species to produce offspring that could retain characteristics of both parental sources yet show significant variations from generation to generation.

Jean Baptiste de Lamarck, working in the late 18th and early 19th century, introduced the concept of increasing complexity and environmental influence on inheritance. Lamarck believed that these characteristics or adaptations were acquired by the parents and then passed on to their offspring.

Charles Robert Darwin, a contemporary of Mendel and Lamarck—working without the benefit of Mendel’s work—provided strong evidence that a species could respond selectively to environmental pressures through successive generations: these adaptations would become manifest in their offspring which would express physical attributes that allowed them to adapt to changes in their environment. But Darwin was unable to explain, like Mendel, and Lamarck, how that happened or explain the vast differences between species and genus.

Researchers in embryology, such as Friedrich Leopold August Weismann (germ plasm theory), Wilhelm Roux (developmental mechanics and research methodology), Hans Adolf Eduard Driesch, and Hugo Marie de Vries (the gene concept, and mutation theory) all working in the period spanning the mid to late 19th through the early decades of the 20th century, looked into the phenomenon of how a cell developed into an entire organism. Biology had come a long way from the homunculus (or animalcules) of Nicolas Hartsoeker in the late 17th century and spontaneous generation of the early Greek philosophers, ancient Babylon, China and India.

None of them, however, were ever able to show how their work related to each other, what mechanisms were at the heart of the phenomena they observed and while many of their conclusions were refuted, they did lay the foundations of genetics and embryology.

It was Thomas H. Morgan who finally provided the last piece of the mysterious puzzle and led to the explosion of scientific research in genetics today. After years of observing and selectively breeding fruit flies (Drosophila melanogaster), Morgan finally made the breakthrough he needed to show that DNA stored on strands of chromosomes held the blueprint for all life forms, how all organisms developed from information stored in genetic material and the primary source which held the answer to how life forms could pass on their characteristics and how changes could possibly develop from generation to generation over the millennia.

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