muller

muller

Hermann Joseph Muller (1890-1967) is an American geneticist. He published 372 papers, published monograph variation caused by single gene change, and participated in the compilation of Mendelian genetic mechanism edited by Morgan. Muller is the founder of radiation genetics, and therefore won the Nobel Prize in physiology and medicine in 1946. The CIB method for mutation detection established by him is still one of the means of biological monitoring.

brief introduction

When we say that mutation is spontaneous, we don't mean that mutation happens for no reason, but that it happens naturally without human intervention. There must be a reason for the mutation, but the reason is unknown, or we did not go deep into it. Sometimes we're not interested, sometimes we don't even need to go into it. However, spontaneous mutation is a kind of mutation with low frequency, and it is just like waiting for the hare. The development of science can not wait for the gift of nature. Scientific research needs new mutations. We must find ways to make it easy to get and improve the efficiency of research work. It was H.J. Muller, Morgan's student, right-hand man and successor who made a breakthrough in this field.
　　

Detailed introduction

Muller was born in New York City on December 21, 1890 and died in Indianapolis on April 5, 1967. Muller was admitted to Columbia University in 1907 and graduated with a bachelor's degree in 1910. During his college years, he read "heredity, variation and evolution" by R. h. lock and studied chromosome genetics taught by Wilson. After graduating from University, he studied in Cornell Medical College and Columbia University Department of science, and obtained a master's degree in 1912. In the same year, he was recruited as a graduate student by Morgan and studied for a doctorate in Morgan's laboratory. In 1916, he obtained his doctorate. From 1916 to 1918, he was invited by J. Huxley, a biologist, to give lectures at the Houston Rice Institute. From 1918 to 1920, Muller returned to Columbia University to continue his research on genetic mutation. From 1921 to 1932, he taught at the University of Texas and became a professor. In 1932, Muller went to Berlin and was arrested by the fascist authorities. Then he was rescued and released. He went to the Soviet Union at the invitation of the Soviet geneticist n.i.vavilov. Working in Leningrad and Moscow Academy of Sciences from 1933 to 1937, he was involved in the dispute with Lisenko, so he left the Soviet Union and joined the Spanish volunteer army. Mueller came to England in 1938 and taught at Edinburgh University until 1940. After that, he returned to the United States, first taught at Amherst College, and then transferred to Indiana University in 1945 until his death. During his lifetime, Muller published 372 papers, published his monograph variation caused by single gene change, and participated in the compilation of Mendelian genetic mechanism edited by Morgan. Muller is the founder of radiation genetics, and therefore won the Nobel Prize in physiology and medicine in 1946. The CIB method for mutation detection established by him is still one of the means of biological monitoring. In 1927, Mueller published a paper entitled "artificial transformation of gene" in the Journal of science, which first confirmed the role of X-ray in inducing mutation, clarified the relationship between mutagen dose and mutation rate, and laid a theoretical foundation for mutation breeding. Specifically, Mueller solved the following problems: (1) sperm treated with high dose of X-ray can induce real gene mutation in germ cells. The so-called real gene mutation is shown from two aspects: one is that the gene with material properties has changed, rather than the chromosomal aberration found in the evening primrose by d'fries; the other is that the changed gene can be truly inherited, after four or more generations of stable inheritance, and most of them show typical Mendelian inheritance. (2) while the Drosophila was treated with X-ray, thousands of untreated Drosophila were used as control. Under the same culture conditions, the mutation rate of Drosophila treated with high dose X-ray was about 150 times higher than that of untreated Drosophila. Hundreds of mutants were obtained in a short time after X-ray treatment, and more than 100 mutant genes were found after several generations of cultivation. (3) mutation types include lethal mutation, half lethal mutation and non lethal mutation. Lethal mutation can be divided into recessive lethal mutation and dominant lethal mutation. There are a lot of dominant lethal mutations, which can be seen from the number of eggs and their effect on sex ratio (dominant lethal causes egg stage death). Many of the induced visible mutations occur at gene loci that have never been seen before, and the phenotypic effects of some of the mutations are not completely similar to those seen before (such as plagioptera, Chlamydomonas, etc.). But most of the mutations have been found in the past, such as white eyes, small wings, forked bristles and so on. This shows that most of the mutations induced by X-ray are the same as those in spontaneous mutation, but the frequency of the latter is much lower. (4) in addition to gene mutation, X-ray can also cause rearrangement of genes on chromosomes, which accounts for a high proportion; it can also cause large chromosome aberrations, such as deletion, breakage, translocation, inversion, etc. (5) X-ray treatment does not result in permanent changes of all the genetic materials on the chromosome, but often affects only a part of them. There are two or more genes in the progeny, and only one of them is mutated. (6) X-ray treatment did not significantly increase the rate of reverse mutation. This shows that the mutation is random, and the mutagens do not favor the mutated genes. (7) treating Drosophila melanogaster with different doses of X-rays at different times and under different conditions of its life cycle will produce different results. Mueller's work shows that the recessive lethal factor does not change directly with the absorbed X-ray energy, but more closely with the square root of the energy. In 1945, the United States dropped its nuclear weapon, the atomic bomb, in Nagasaki and Hiroshima. People are deeply impressed by the tremendous explosive power and mass destruction effect of atomic bomb. However, are the victims of the atomic bomb only casualties? Are those who don't die or hurt not affected at all? Before that, people had been dealing with radioactive materials for more than 40 years, but they knew little about their biological effects, especially their genetic effects. Mueller clearly pointed out in his paper: "the radiation treatment practice commonly used in modern X-ray therapy will definitely not cause permanent infertility. This is mainly based on a purely theoretical concept, which is that the eggs produced after the recovery of pregnancy must represent the" undamaged "tissue This assumption is proved wrong here... " Mueller won the Nobel Prize in physiology and medicine in 1946 for his work in 1927, which indicates that the human understanding of mutation has become mature. Subsequently, "Genetics in the atomic age" and "radiation genetics" became hot spots. Other physical or chemical mutagens were found and studied one by one. In order to maintain human health, more and more attention has been paid to the detection of teratogenic, carcinogenic and mutagenic environmental factors.

Chinese PinYin : Miu Le