Hermann Joseph Muller facts for kids
Quick facts for kids
Hermann Joseph Muller
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Hermann J. Muller speaking at the 1952 World Science Fiction Convention
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| Born | December 21, 1890 New York City, U.S.
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| Died | April 5, 1967 (aged 76) Indianapolis, Indiana, U.S.
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| Alma mater | Columbia University |
| Known for | The genetic effects of radiation |
| Spouse(s) |
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| Children | 2 |
| Awards | 1927
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| Scientific career | |
| Fields | Genetics, molecular biology |
| Doctoral advisor | Thomas Hunt Morgan |
| Doctoral students | H. Bentley Glass |
| Influences | J. T. Patterson |
Hermann Joseph Muller (born December 21, 1890 – died April 5, 1967) was an American scientist who studied genetics. He was also a teacher and won a Nobel Prize. He is best known for his important work on how radiation affects living things and their genes. This process is called mutagenesis, which means causing changes in DNA.
Muller was also known for his strong opinions on social issues. He often warned people about the long-term dangers of radioactive fallout from nuclear war and nuclear testing. His warnings made people pay more attention to these practices.
Contents
Early Life and Education
Hermann Muller was born in New York City. His father worked with metals. Muller's family had lived in America for several generations. His father's family came from Germany, and his mother's family came from Britain. One of his famous cousins was Alfred Kroeber, who was the father of writer Ursula K. Le Guin.
As a teenager, Muller went to a Unitarian church and believed in pantheism, which is the idea that God is everything in the universe. In high school, he became an atheist. He was a very good student in public schools.
At 16, he started college at Columbia University. From his very first semester, he was interested in biology. He quickly believed in the Mendelian-chromosome theory of how traits are passed down. This theory also included the idea of mutations (changes in genes) and natural selection as the basis for evolution.
Muller started a biology club and also became interested in eugenics. Eugenics is the idea of improving the human race through controlled breeding. He always cared about how biology connected with society. He earned his first degree in 1910.
Muller continued his studies at Columbia for graduate school. He became interested in the work of Thomas Hunt Morgan's lab, which studied genetics using Drosophila (fruit flies). Muller joined Morgan's group in 1912. In the lab, Muller mostly came up with new ideas and explanations for experiments. He felt that he didn't always get enough credit for his ideas.
Scientific Career and Discoveries
In 1914, Muller took a job at the William Marsh Rice Institute, now called Rice University. He finished his PhD degree and moved to Houston in 1915. At Rice, Muller taught biology and kept working with fruit flies.
In 1918, he explained why some plants, like Oenothera lamarckiana, seemed to have sudden, big changes. He said these changes were due to "balanced lethals," which allowed hidden gene changes to build up. Rare crossing over events then made these hidden traits suddenly appear. This showed that these changes could be explained by the Mendelian-chromosome theory. Muller's work increasingly focused on how often mutations happen and on lethal mutations (gene changes that cause death).
Later in 1918, Muller returned to Columbia University to teach and expand his research. There, he and his friend Edgar Altenburg continued to study lethal mutations. They looked at the sex ratios of fruit fly offspring. They predicted that if there were recessive mutations on the X chromosome, the ratio would change because these mutations would only show up in males. Muller found that temperature affected how often mutations happened. This made him think that most mutations happened naturally, rather than from outside factors like radiation.
In 1919, Muller made an important discovery: a mutant fly that seemed to stop crossing over (when chromosomes exchange parts). This opened up new ways to study mutation rates. However, his job at Columbia didn't continue, so he moved to the University of Texas in 1920.
X-ray Mutagenesis Discovery
Muller taught at the University of Texas from 1920 to 1932. Soon after arriving, he married mathematics professor Jessie Marie Jacobs. In his early years there, his fruit fly work was slow. The data from his mutation studies were hard to understand.
In 1923, he started using radium and X-rays in his experiments. But it was hard to measure the link between radiation and mutation because the radiation also made the flies unable to have babies. During this time, he also became more involved with eugenics and human genetics. He studied twins who were separated at birth, and his work suggested that IQ had a strong genetic component.
Muller disagreed with some of the new directions of the eugenics movement, like anti-immigration ideas. But he was hopeful about "positive eugenics," which aimed to improve humanity. In 1932, he gave a speech saying that eugenics could make the human race better, but only in a society organized for everyone's good.
In 1926, Muller made a huge breakthrough. He did two experiments with different amounts of X-rays. The second experiment used a special fly strain he had found in 1919. He quickly found a clear link between radiation and lethal mutations. This discovery caused a lot of excitement in the news after he presented his findings in Berlin. It made him a well-known public figure in the early 20th century. By 1928, other scientists had repeated his results, even with other animals like wasps and plants like maize. In the years that followed, he started warning people about the dangers of radiation exposure for humans, such as doctors who often used X-ray machines.
His lab grew quickly, but it got smaller during the Great Depression. Muller became more and more worried about capitalism. Some of his lab visitors were from the USSR, and he helped with a student newspaper called The Spark. This was a tough time for Muller, both in his science and his personal life. His marriage was ending, and he was unhappy with his life in Texas. Also, the eugenics movement was losing popularity, partly because his own work showed how much the environment affected genetics. This meant his ideas about human evolution had less public impact.
Work in Europe
In September 1932, Muller moved to Berlin to work with a Russian geneticist. This trip, meant to be short, turned into an eight-year journey through five countries. In Berlin, he met important physicists like Niels Bohr and Max Delbrück. The Nazis were causing many scientists to leave Germany, and Muller strongly opposed their ideas.
The FBI was investigating Muller because of his involvement with The Spark. So, he decided to go to the Soviet Union, which he felt was a better place for his political beliefs. In 1933, Muller and his wife got back together, and they and their son David E. Muller moved to Leningrad. There, he set up a fruit fly lab at the Institute of Genetics. The institute moved to Moscow in 1934, and Muller and his wife divorced in 1935.
In the USSR, Muller led a large and productive lab. He also organized work on medical genetics. Most of his research involved further studies of genetics and radiation. He finished his eugenics book, Out of the Night, which had ideas he'd been thinking about since 1910. However, by 1936, Joseph Stalin's strict rules and the rise of Lysenkoism made the USSR a difficult place to live and work. Muller and many Russian geneticists tried to oppose Trofim Lysenko and his ideas about evolution. But Muller was soon forced to leave the Soviet Union after Stalin read his eugenics book and didn't like it.
Muller, with about 250 types of fruit flies, moved to the University of Edinburgh in September 1937, after short stays in Madrid and Paris. In 1938, with war approaching, he started looking for a permanent job back in the United States. He also began dating Dorothea "Thea" Kantorowicz, a German refugee. They married in May 1939. The Seventh International Congress on Genetics was held in Edinburgh later that year. Muller wrote a "Geneticists' Manifesto" to answer the question: "How could the world's population be improved most effectively genetically?"
Later Career and Nobel Prize
When Muller returned to the United States in 1940, he took a research job at Amherst College. After the U.S. entered World War II, his job was extended and included teaching. His fruit fly work during this time focused on measuring how often natural mutations happened, not just those caused by radiation. He published less during this period because he had fewer lab workers and his projects were very challenging. However, he also advised the Manhattan Project (though he didn't know its true purpose at the time) and studied how radar affected mutations.
Muller's job at Amherst ended in 1945. Despite some difficulties because of his socialist political activities, he found a job as a professor of zoology at Indiana University. He lived in a Dutch Colonial Revival style house in Bloomington.
In 1946, Muller won the Nobel Prize in Physiology or Medicine. He received it "for the discovery that mutations can be induced by X-rays." Genetics, especially understanding the physical nature of genes, was becoming a very important topic in biology. X-ray mutagenesis was key to many recent advances. For example, George Beadle and Edward Tatum's work on Neurospora in 1941 established the idea that one gene makes one enzyme. In Muller's Nobel Prize speech, he argued that even very small amounts of radiation could cause mutations. This led to the idea that there is no safe level of radiation exposure when it comes to cancer risks.
After the atomic bombings of Hiroshima and Nagasaki, the Nobel Prize brought public attention to the dangers of radiation, a topic Muller had been talking about for twenty years. In 1952, nuclear fallout became a public issue. More and more evidence was coming out about radiation sickness and deaths caused by nuclear testing. Muller and many other scientists worked hard to reduce the threat of nuclear war. After the Castle Bravo fallout event in 1954, the issue became even more urgent.
In 1955, Muller was one of 11 famous thinkers to sign the Russell–Einstein Manifesto. This led to the first Pugwash Conference on Science and World Affairs in 1957, which focused on controlling nuclear weapons. He also signed a 1958 petition to the United Nations, along with many other scientists, calling for an end to nuclear weapons testing. This petition was started by Nobel Prize-winning chemist Linus Pauling.
Muller's ideas about how radiation causes mutations were used by Rachel Carson in her famous book Silent Spring. However, some scientists, like geneticist James F. Crow, called Muller's views "alarmist." They said his views created "an irrational fear of low-level radiation" compared to other risks. Some argue that Muller's opinion wasn't fully supported by studies on the survivors of the atomic bombings or by research on mice. They also say he ignored a study that went against his ideas, which affected how policies about radiation safety were made.
Muller received the Linnean Society of London's Darwin–Wallace Medal in 1958 and the Kimber Genetics Award in 1955. He was president of the American Humanist Association from 1956 to 1958. He retired in 1964. The basic units of inheritance in fruit flies, their chromosomal arms, are named "Muller elements" in his honor.
H. J. Muller and science fiction writer Ursula K. Le Guin were distant cousins. His father and her father's mother were siblings. Another cousin was Herbert J. Muller.
Family Life
Hermann Muller had two children. His daughter, Helen J. Muller, became a professor at the University of New Mexico. She has a daughter named Mala Htun, who is also a professor. His son, David E. Muller, was a professor of mathematics and computer science at the University of Illinois and New Mexico State University. David's mother was Jessie Jacobs Muller Offermann, Hermann's first wife. Helen's mother was Dorothea Kantorowicz Muller, Hermann's second wife, who came to the U.S. in 1940 as a German refugee.
Notable Students and Colleagues
Muller taught and worked with many important scientists. Here are a few:
- Raissa L. Berg
- Elof Axel Carlson
- H. Bentley Glass
- C. P. Oliver
- Wilson Stone
Some postdoctoral fellows who worked with him include:
Even as an undergraduate, Carl Sagan worked in Muller's lab.
See also
- Mutagenesis
- Bateson–Dobzhansky–Muller model
- Muller's ratchet
- Muller's morphs
- History of biology
- History of genetics
- History of model organisms
Images for kids
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In Spanish: Hermann Joseph Muller para niños
