drosophilia, fruit fly, fruit fly genome, genetic mutations, genetics, Hermann Joseph Muller, human genome, immune system, impacts radiation on immunity, infertility, lethal mutations, Muller, Nobel Prize in Physiology Medicine, nuclear energy, nuclear safety, nuclear waste, radiation induced mutations, radioactive fallout, radium, x-ray mutagenesis
“Hermann Joseph Muller (or H. J. Muller) (December 21, 1890 – April 5, 1967) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (X-ray mutagenesis) as well as his outspoken political beliefs. Muller frequently warned of the long-term dangers of radioactive fallout from nuclear war and nuclear testing, helping to raise public awareness in this area.
… At 16 he entered Columbia College. From his first semester he was interested in biology; he became an early convert of the Mendelian-chromosome theory of heredity — and the concept of genetic mutations and natural selection as the basis for evolution… Muller earned a B.A. degree in 1910.
Muller remained at Columbia (the pre-eminent American zoology program at the time, thanks to E. B. Wilson and his students) for graduate school. He became interested in the Drosophila [fruit fly] genetics work of Thomas Hunt Morgan’s fly lab…
In 1911-1912, he studied metabolism at Cornell University, but remained involved with Columbia. He followed the drosophilists as the first genetic maps emerged from Morgan’s experiments, and joined Morgan’s group in 1912 (after two years of informal participation). In the fly group, Muller’s contributions were primarily theoretical: explanations for experimental results and ideas and predictions for new experiments…
In 1914, Julian Huxley offered Muller a position at the recently founded William Marsh Rice Institute, now Rice University; he hurried to complete his Ph.D. degree and moved to Houston for the beginning of the 1915-1916 academic year (his degree was issued in 1916). At Rice, Muller taught biology and continued Drosophila lab work. In 1918, he proposed an explanation for the dramatic discontinuous alterations in Oenothera larmarckiana that were the basis of Hugo de Vries’s theory of mutationism: “balanced lethals” allowed the accumulation of recessive mutations, and rare crossing over events resulted in the sudden expression of these hidden traits. In other words, de Vries’s experiments were explainable by the Mendelian-chromosome theory. Muller’s work was increasingly focused on mutation rate and lethal mutations. In 1918, Morgan—short-handed because many of his students and assistants were drafted for the U.S. entry into World War I—convinced Muller to return to Columbia to teach and to expand his experimental program.
At Columbia, Muller and his collaborator and longtime friend Edgar Altenburg continued the investigation of lethal mutations. The primary method for detecting such mutations was to measure the sex ratios of the offspring of female flies. They predicted the ratio would vary from 1:1 due to recessive mutations on the X chromosome, which would be expressed only in males (who lacked the functional allele on a second X chromosome). Muller found a strong temperature dependence in mutation rate, leading him to believe that spontaneous mutation was the dominant mode (and to initially discount the role of external factors such as ionizing radiation or chemical agents). In 1920, Muller and Altenburg coauthored a seminal paper in Genetics on “modifier genes” that determine the size of mutant Drosophila wings. In 1919, Muller made the important discovery of a mutant (later found to be a chromosomal inversion) that appeared to suppress crossing-over, which opened up new avenues in mutation rate studies. However, his appointment at Columbia was not continued; he accepted an offer from the University of Texas and left Columbia after the summer of 1920.
Muller taught at The University of Texas from 1920 until 1932… In his early years at Texas, Muller’s Drosophila work was slow going; the data from his mutation rate studies were difficult to interpret. In 1923, he began using radium and X-rays, but the relationship between radiation and mutation was difficult to measure because such radiation also sterilized the flies…
Discovery of X-ray mutagenesis
1926 marked the beginning of a series of major breakthroughs. Beginning in November, Muller carried out two experiments with varied doses of X-rays, the second of which used the crossing over suppressor stock (“ClB”) he had found in 1919. A clear, quantitative connection between radiation and lethal mutations quickly emerged. Muller’s discovery created a media sensation after he delivered a paper entitled “The Problem of Genetic Modification” at the Fifth International Congress of Genetics in Berlin; it would make him one of the better known public intellectuals of the early 20th century. By 1928, others had replicated his dramatic results, expanding them to other model organisms such as wasps and maize. In the following years, he began publicizing the likely dangers of radiation exposure in humans (such as physicians who frequently operate X-ray equipment).
In 1946 Muller was awarded the Nobel Prize in Physiology or Medicine, “for the discovery that mutations can be induced by x-rays”. Genetics, and especially the physical and physiological nature of the gene, was becoming a central topic in biology, and x-ray mutagenesis was a key to many recent advances, among them George Beadle and Edward Tatum’s work on Neurosporathat established the one gene-one enzyme hypothesis.
The Nobel Prize, in the wake of the atomic bombings of Hiroshima and Nagasaki, focused public attention on a subject Muller had been publicizing for two decades: the dangers of radiation. In 1952, nuclear fallout became a public issue; since Operation Crossroads, more and more evidence had been leaking out about radiation sickness and death caused by nuclear testing, and Muller was one of the foremost experts. Muller—and many other scientists—pursued an array of political activities to defuse the threat of nuclear war. With the Castle Bravo fallout controversy in 1954, the issue became even more urgent. In 1955 Muller was one of eleven prominent intellectuals to sign the Russell-Einstein Manifesto, the upshot of which was the first Pugwash Conference on Science and World Affairs in 1957, which addressed the control of nuclear weapons. He was a signatory (with many other scientists) of the 1958 petition to the United Nations, calling for an end to nuclear weapons testing, which was initiated by the Nobel Prize-winning chemist Linus Pauling.
Excerpted from: https://en.wikipedia.org/wiki/Hermann_Joseph_Muller (Emphasis our own; See references at blog post bottom)
“THE FREQUENCY OF TRANSLOCATIONS PRODUCED BY X-RAYS IN DROSOPHILA ” H. J. MULLER University o f Texas, Austin, Texas AND EDGAR ALTENBURG Rice Institute, Houston, Texas Received September 13, 1929 https://web.archive.org/web/20100706003801/http://www.esp.org/foundations/genetics/classical/holdings/m/HJM-v15-n4-p283-io.pdf
White Eye Fruitfly mutation: https://en.wikipedia.org/wiki/White_(mutation)
“The common fruit fly (Drosophila melanogaster) is an important animal model for the human immune system, making it a useful model for studying the biological effects of spaceflight. Spaceflight affects the innate immune system, which could make animals including humans more susceptible to disease, especially because microbes can become hardier and more virulent in space. The NASA Ames Research Center (ARC) ISS Drosophila Experiment (Fruit Fly Lab-01) studies the combined effect of altered host immunity with changes to microbes in space.” http://www.nasa.gov/mission_pages/station/research/experiments/1116.html
“A 1-g centrifuge will subject Drosophila to the equivalent of Earth-gravity, allowing researchers for the first time to unravel the competing influences of radiation and gravity.”
Fruitfly and Human Genome Have Been Mapped
“fruit flies, known to scientists as Drosophila melanogaster, are commonplace in genetic research labs. They can be good substitutes for people. They reproduce quickly, so that many generations can be studied in a short time, and their genome has been completely mapped. Drosophila is being used as a genetic model for several human diseases including Parkinson’s and Huntington’s.”
The US Department of Energy helped to coordinate-fund the human genome project “Completed in 2003, the Human Genome Project (HGP) was a 13-year project coordinated by the DOE and the National Institutes of Health to sequence the 3 billion basepairs that make up human DNA.” http://genomics.energy.gov
The US DOE oversees US nuclear labs and their radioactive waste…
References for the Wikipedia article:
1. Pontecorvo, G. (1968). “Hermann Joseph Muller. 1890-1967”. Biographical Memoirs of Fellows of the Royal Society 14: 348–326. doi:10.1098/rsbm.1968.0015.
2. Carlson, Elof Axel (1981). Genes, radiation, and society: the life and work of H. J. Muller. Ithaca, N.Y: Cornell University Press. ISBN 0-8014-1304-4.
3. John Bellamy Foster (2009). The Ecological Revolution: Making Peace with the Planet, Monthly Review Press, New York, pp. 71-72.
5. Carlson, Genes, Radiation, and Society, pp 17-37
6. Carlson, Genes, Radiation, and Society, pp 37-69
7. Carlson, Genes, Radiation, and Society, pp 70-90; for more on the culture and norms of the fly lab, see Kohler, Robert E. (1994). Lords of the fly: Drosophila genetics and the experimental life. Chicago: University of Chicago Press. ISBN 0-226-45063-5..
8. Carlson, Genes, Radiation, and Society, pp 91-108
9. Carlson, Genes, Radiation, and Society, pp 109-119
10. Carlson, Genes, Radiation, and Society, pp 120-140
11. Carlson, Genes, Radiation, and Society, pp 141-164
20. Carlson, Genes, Radiation, and Society, pp 304-318
21. Carlson, Genes, Radiation, and Society, pp 336