Calvin Bridges

Calvin Blackman Bridges (January 11, 1889 – December 27, 1938) was an American scientist, known for his contributions to the field of genetics. Along with Alfred Sturtevant and H.J. Muller, Bridges was part of the famous fly room of Thomas Hunt Morgan at Columbia University.

Early life

Calvin Blackman Bridges was born in Schuyler Falls, New York in 1889 to the parents of Leonard Bridges and Charlotte Blackman. Tragically, Calvin's mother died when he was two years old, and his father died a year after his mother's death, leaving Calvin Bridges an orphan. Following the death of his parents, Bridges was taken in and raised by his grandmother. Despite now being known in the scientific world as one of the most influential researchers regarding Drosophila melanogaster, it took Bridges several years to complete high school, graduating when he was 20 years old. However, despite this set back, Bridges moved on to be an outstanding student at Columbia University, where he attended both for undergraduate and postgraduate school. While taking a class on zoology, Bridges met Thomas Hunt Morgan. This started a relationship that would lead to many important discoveries in the scientific world regarding genetics and evolution. Calvin Bridges went on to marry Gertrude Ives and have four children. Bridges was known to be both brilliant and a very kind and considerate man by all who knew him.^[1]

Work and Research

The "Fly Room" experiment began in 1910, with Thomas Hunt Morgan being the main experimental developer. Working alongside Bridges and Hunt included two other scientists named Alfred Sturtevant and Hermann Joseph Muller. The "Fly Room" experiment took place for seventeen years,^[2] yielding significant results in regards to the field of genetics. The experiment used Drosophila melanogaster, commonly known as fruit flies, because they are cheap, accessible, and reproduce quickly. This provides many generations of fruit flies in a short amount of time, which was a key aspect for this experiment.^[3] The "Fly Room" experiment resulted in discoveries that explained many issues such as sex chromosome linkage, genetic information in chromosomes, and chromosomal arrangement. These men also contributed to the understanding of mutations on evolution and genetics in general.^[4]

Calvin Bridges was responsible for many improvements regarding the techniques and the equipment used in the "Fly Room" experiment. He suggested the men use binocular microscopes instead of the hand lenses they had been using before, which improved data quality. Also, he developed temperature controls for the experiment that proved to be more useful and yielded better results than the previous temperature controls.^[5]

Bridges published many works, one of his most famous being "Sex in Relation to Chromosomes and Genes".^[6] Also, Bridges contributed many items to the Journal of Experimental Zoology and Science. He was also elected to the National Academy of Sciences in 1936 for his work with Drosophila.^[7]

Bridges wrote a masterful Ph.D. thesis on "Non-disjunction as proof of the chromosome theory of heredity." It appeared as the first paper in the first issue of the journal Genetics in 1916.

His work with sex linked traits in the fruit fly Drosophila melanogaster suggested that chromosomes contained genes. Later Nettie Maria Stevens was able to prove this hypothesis by examining the chromosomes of the fruit flies. Bridges wrote a couple of papers presenting the proof. He thanked her as "Miss Stevens" without stating what her contribution was nor referring to her PhD.

After his death, Bridges' student Katherine Brehme Warren completed work on The Mutants of Drosophila melanogaster (1944), a classic book which was for two decades an indispensable resource for geneticists.^[8]

Bridges' best-known contribution among Drosophila researchers is his observation and documentation of the polytene chromosomes found in larval salivary gland cells. The banding patterns of these chromosomes are still used as genetic landmarks even by contemporary researchers.

References

Sources

1. "Bridges, Calvin Blackman." Complete Dictionary of Scientific Biography. Vol. 2. Detroit: Charles Scribner's Sons, 2008. 455-457. Gale Virtual Reference Library. Web. 26 January 2015.

2. Muhlrad, Paul J. "Fruit Fly: Drosophila." Genetics. Ed. Richard Robinson. Vol. 2. New York: Macmillan Reference USA, 2003. 42-45. Gale Virtual Reference Library. Web. 26 January 2015.

3. "Bridges, Calvin Blackman." Britannica Biographies (2012): 1. Middle Search Plus. Web. 26 January 2015.

Further reading

• Allen, Garfield E. Thomas Hunt Morgan: the man and his science. Princeton University Press 1978
• E.A. Carlson, Mendel's Legacy: The Origin of Classical Genetics, (Cold Spring Harbor Laboratory Press, 2004). ISBN 0-87969-675-3
• E.A. Carlson, The Gene: A Critical History, (Iowa State Press, 1989). ISBN 0-8138-1406-5
• Kohler, Robert E. Lords of the fly: Drosophila genetics and the experimental life. University of Chicago Press 1994.
• A. H. Sturtevant, A History of Genetics, (Cold Spring Harbor Laboratory Press,2001). ISBN 0-87969-607-9

External links

• National Academy of Sciences Biographical Memoir
• Works by Calvin Bridges at Project Gutenberg
• Works by or about Calvin Bridges at Internet Archive