Hermann Joseph Muller

The American geneticist Hermann Joseph Muller (1890-1967) was the first to induce mutations in an organism by severe x-ray treatment.

Hermann J. Muller was born in New York City on Dec. 21, 1890. His father died before Hermann was 10 years old, but he had already been imbued by his father with a sense of the grandeur of evolution and a sympathy for oppressed people. After graduation from Morris High School in the Bronx, he entered Columbia University. After receiving a master's degree there in 1911, he continued his studies at the Medical School of Cornell University for a year, returning to Columbia University for his doctorate, which he received in 1916.

At Columbia University Muller came under the influence of Thomas Hunt Morgan, who had gathered together a group of young researchers to study genetic inheritance in fruit flies (Drosophila melanogaster). Muller worked with this group in 1910 and discovered a fly mutant which established the reality of the "M," or fourth, chromosome of the fruit fly. In 1915 Muller joined the biology department of Rice Institute, but 3 years later he returned to Columbia for 2 years of research and teaching. In 1920 he went to the University of Texas.

In 1926 Muller reported at the Sixth International Congress of Genetics in Berlin that he had succeeded in jolting the genes in the chromosomes of the fruit fly; that is, his x-rays had broken them apart and rearranged them, resulting in an increase in the mutation rate 150-fold. He had thus artificially accelerated the evolutionary process. Controlled mutation was now a fact, and overnight, at the age of 36, Muller became famous. For this classic experiment he was awarded the Nobel Prize in medicine in 1946. In 1945 Muller was called to Indiana University in Bloomington to become distinguished service professor of zoology. He remained there until his death.

Muller had a strong social awareness and believed that his own researches and the work of other scientists should be used to improve the genetic composition of mankind as well as the general living conditions of all people. He held that the ultimate objective of his own work was "the control of the evolution of man by man himself." After the severe depression that struck the United States in 1929, Muller, who had become sympathetic with some form of socialism, left Texas to work in Germany. But having seen the rise of Nazism, he went on to the Soviet Union in 1933. He was given a laboratory in the Institute of Genetics in Moscow, where he worked as senior geneticist for almost 4 years. However, Trofim Lysenko, who was violently opposed to the Morgan theory of the gene and preached the Lamarckian view of the inheritance of acquired characters, was able to win the political favor of Stalin, and his theory became the official doctrine of heredity in Russia. Those who taught and did research along the lines of Morgan's school of genetics were dismissed or harassed. Muller became disillusioned, left the country, and denounced Russian communism.

In 1955, together with Albert Einstein and other famous scientists, he signed an appeal to all countries to forswear war in view of the danger that the hydrogen bomb would threaten the health of future generations and even the existence of mankind. He campaigned vigorously against the use of nuclear bomb tests because of the harmful mutations that would result. Muller was also interested in the quality of man's life in the future and went so far as to urge the freezing of sperm of gifted men for use after their death in artificial insemination. He fought for the promotion of sperm banks, an idea that provoked bitter criticism.

Between 1955 and 1959 Muller served as president of the American Humanist Association and was president also of the newly launched American Society of Human Genetics. He was a member of many scientific societies as well as of the American Philosophical Society. Muller died of a heart ailment on April 5, 1967.

Further Reading

• Muller's unpublished autobiographical notes, written in 1936, are now in the Lilly Rare Books Library of Indiana University. A popular account of his life and achievements is in Bernard Jaffe, Men of Science in America (1944; rev. ed. 1958).