Thomas Hunt Morgan

Irma Reyes

Lil' Thomas

Thomas Hunt Morgan was born on September 5th of 1866(1). He was born in Lexington, Kentucky(1). His family was an influential, wealthy, southern family(1). As a young child Morgan seemed very intrigued by natural sciences. This curiosity of natural sciences lead him to his career as a geneticist.


As a young boy living in the country, Morgan didn't always have much to do. Most of his time was spent outside in nature. He developed a strong curiosity towards the natural sciences. He would collect birds, birds nest, fossils(2). Once he was grown and graduated he spent time at a seashore laboratory(2). He spent a lot of his time in nature based labs which led him to be the zoologist and geneticist that he is(2).


He was born around the ending of the Civil War(4) This caused his family great trouble because being from the South meant they were confederates. The confederates were more or less being punished by the State. This made life difficult and not advanced for Morgan. He spent most of his time outside in the nature. This helped him become who he was, a scientist, and a great one at that.

Fly Room

Morgan began to breed the common fruit fly (Drosophila Melanogaster) in 1907. His laboratory in Columbia University came to be nicknamed the "Fly Room" because of all the flies(3) It took him about three years of breeding to finally come across a distinctive different feature, which were white eyes instead of red(3) After noticing this he chose to breed that (male) fly with a normal red-eyed fly(3). The first generation between this white-eyed male and red-eyed female only produced three white-eyed flies out of 1,237(3) The second generation had considerably a larger amount of white-eyed flies, all male(3)


Morgan was skeptical of the Mendelian Theory of Inheritance, the chromosomal theory, and Darwin's theory that natural selection could be a reason for the creation or appearance of new species(3). He found it difficult that the changes in species could be at cause of slight chance variations(6). But after having found these white-eyed male flies, he started to reconsider each of these ideas(3). One of the ideas that he largely reconsidered was the idea that eye color and sex had some type of basis in the chromosomes. He noted that the male flies' chromosomes were XY and the female flies' chromosomes were XX(3). He realized that if the eye color factor was in the X chromosome, that the Mendelian Theory of Inheritance could apply(3)

Sex-Linked Traits

The first generation offspring from the white-eyed male and the red-eyed female, was majority red-eyed because they had the X chromosome, which was the dominant trait(3). But since the offspring received the male's recessive X chromosome for white-eyes, then that trait would be passed down to the second generation and about half of them would have white-eyes(3) Morgan was able to find more mutant traits. This led him to refine Mendelian laws and add the theory that chromosomes carried hereditary information(3). He argued that a single chromosome couldn't carry all that information(6). His experiment helped prove that. He stated that both the eggs and the sperm carried factors that could determine traits(5) He basically coined the term genes as the information on the chromosome(3). He opened up the pathway for more research in genetics and a revolution in Biology.


Darwin Medal in 1924

Nobel Prize for Physiology or Medicine in 1933

Copley Medal 1939

Thomas Hunt Morgan and Fruit Flies: A Comedy
Thomas Hunt Morgan Tasha Nelson


  1. "Thomas Hunt Morgan." Famous Scientists. Famous Scientists, n.d. Web. 09 Dec. 2014
  2. "Thomas H. Morgan - Biograpical" . Nobel Media AB 2013. Web 10 Dec 2014
  3. "Genetics and Genomics Timeline." GNN - Genetics and Genomics Timeline. J. Craig Venter Institute, n.d. Web 11 Dec. 2014
  4. "The Thomas Hunt Morgan Medal." Genetics Society of America., n.d. 12 Dec. 2014
  5. Mueller, Michelle. "Pangenesis," The Path to the Chromosome Theory of Heredity. N.p., 2001. Web. 12 Dec. 2014
  6. Allen, Garland Edward. "Thomas Hunt Morgan (American Biologist). Encyclopedia Britannica Online. Encyclopedia Britannica, n.d Web. 12 Dec. 2014