Hugo De Vries (February 16,1848 - May 21, 1935)
De Vries is one of the first geneticists. Both De Vries and Mendel had worked on the research of the discovery of the law of heredity with the unawareness of each other. He is also known suggesting the concept of the genes. In which himself called this particle contains inheritance traits as pangenes. He introduced the theory of mutation, in which he believed species evolve one from another through sudden changes in traits.
Thomas Hunt Morgan ( September 25, 1866 - December 4, 1945)
Morgan was initially again the theory of chromosomes contain inheritance traits. He worked with his students in Columbia University, together they studied the reproduction of the Drosophila melanogaster (a common seen type of fruit flies). He then became a big supporter of the idea of the chromosomes passes down the inheritance traits. Morgan and his students provided proofs for the chromosomal theory of inheritance. They also worked out the evidence for genetic linkage in which is the concept that there are more than one genes located on the same chromosome. Their research also include non-disjunction and chromosomal crossing over.
Walter S.Sutton (April 5, 1877 - November 10, 1916)
Sutton is an American scientist who applied Medal's Law of inheritance to the chromosomes and concluded the chromosomes are the basis of inheritance. He observed each chromosome in the grasshoppers' cell are clearly different. The chromosomes reduce the number of chromosomes in gametes. Sutton published his work in 1903. However, he never finished his research. He entered medical school and became a surgeon, then served in WWI as a doctor. He died at age of 39.
Rosalind Franklin (July, 25,1920-April 16,1958)
She is the first person who took a clear picture of the structure of DNA with X-ray diffraction technique. In which later it has helped Watson and Crick with the building the 3D molecular structure of DNA. Her picture of DNA has shown a clear "X" shape. This discovery prompted Watson and Crick that DNA is not a straight ladder but instead it is a twisted double helix. The Double Helix structure is "protecting" the hydrogen bonds in DNA from denaturing by the water. Unfortunately, she died 4 years earlier before the Nobel Prize in 1962 most likely due to the frequent exposure to X-ray.
Barbara McClintock (June 16, 1902 - September 2, 1992)
McClintock awarded the Nobel Prize of 1983 in Physiology or Medicine for her discovery of the transposition of corn chromosomes. She realized the maize (corn) husks have different colors and the corn kernels have spots. She worked on her observation at the Cold Spring Harbor Laboratory. McClintock then found the existence of "jumping" genes, she is the first one who recognized this element. She concluded from her work that the small segment of DNA "jumps" between different chromosomes, and this action leads to activate or deactivate of certain traits.
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