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The "Queen of Corn" who loves science Barbara McClintock, first female scientist in the field of genetics

The "Queen of Corn" who loves science

Barbara McClintock, first female scientist in the field of genetics




Someone once said that in the first half of the 20th century, there were no 26 English letters in the genetics community, only one, that is, M.

M represents the well-known founder of genetics Mendel (Mendel GJ) and genetics pioneer Morgan (Morgan TH), and one is the master of genetics Barbara McClintock (McClintock B. ).

Unlike Mendel's discovery of the famous genetic law and the creation of chromosome genetic theory by Morgan, McClintock's discovery of "jumping genes" is not well known to the public. Not only that, this discovery has been recognized by the scientific community and has experienced a long wait of more than thirty years.

In 1983, the 81-year-old American female scientist McClintock, the discoverer of the "jumping gene", won the Nobel Prize in Physiology or Medicine, becoming the first female scientist in the field of genetics to independently receive the award.

This female scientist who has been struggling for life in the field of genetics has never been married in her life. She deeply "bells" her love in genetics and "bell" in science.

Science woman

McClintock, born in 1902, is a well-known botanist and genetic immunologist in the United States. After obtaining a Ph.D. in botany from Cornell University ’s College of Agriculture in 1927, he was engaged in the research of corn cell genetics for life.

When he received his PhD in botany, McClintock was under 25 years old and was hired as a lecturer by Cornell University. At that time, the Drosophila research group led by California Institute of Technology Morgan had confirmed that "linkage groups" (hereditary genomes) were on specific chromosomes. Cornell University's corn genetics research team, led by the famous corn geneticist Rawlins A. Emerson, intends to do the same, record specific linkage groups, and associate it with specific chromosomes.

The primary task of McClintock is to locate markers of known genetic characteristics on each corn chromosome. Although the corresponding work has been fully developed in fruit flies, it has barely begun in plants.

As a key member of the group, McClintock ’s outstanding insight has kept her at the forefront of science. When Emerson ’s research was limited to maize genetics through breeding, McClintock had opened up new fields in cytology.

She combined the two disciplines of cytology and genetics, and the accuracy and detail of the research were significantly improved. However, this approach was not only unheard of for many genetics researchers at the time, but also made it difficult for many people to understand the work of McClintock. Meaning.

However, these did not make McClintock care. In her impressions, the old days are particularly enjoyable-in Cornell's cornfield, articles were written one after another at the same time. From 1929 to 1931, she published a total of 9 papers detailing her explorations: in maize chromosome morphology; in successfully linking cytological markers to known genetic markers. Each of her explorations has made important contributions to genetics.

Especially in 1931, she and her student Harriet Creighton published a paper in the "National Academy of Sciences Records Compilation", which confirmed that the exchange of genetic information that occurred during the formation of sex cells was carried out together with the exchange of chromosomal materials. Yes, it provides confirmation for the chromosomal basis of genetics and is recognized internationally.

However, in the era of McClintock, women with scientific knowledge would rather be skilled workers and teachers than scientists. Science is just a hobby to them rather than a means of earning a living. Because the position of researcher is not their turn. Even if McClintock has a place in the scientific community, this status quo cannot be changed.

In 1936, with the help of his friend Lewis Stade at the University of Missouri, McClintock finally obtained the position of assistant professor at the University of Missouri. Here, she owns a laboratory, an opportunity for her to continue her research work.

Since then, she has worked hard to track the dynamics of chromosome mutations. After completing the study of ring chromosomes, she turned to studying the re-annealing of broken chromosomes. She found that in all cells of the organism, the cycle of breaking-healing-bridge is repeated many times in the life history of the plant. When the fractured end no longer heals, the cycle ends.

This research result has been reported in a series of papers since 1938, which has aroused great interest in academia. In 1939, she was elected vice president of the American Genetic Society. However, the increasing academic reputation has not improved McClintock ’s position at the University of Missouri. Not only that, the department did not even notify her of the work provided by other agencies, and her uncomfortable professional position caused her great pain.

In the summer of 1940, the Dean wanted McClintock to leave. However, a year later, the dean regretted the decision he had made. He heard that McClintock had been nominated as an academician of the American Academy of Sciences, and persuaded her to come back and promised him a promotion. But it was too late, McClintock went to the Cold Spring Harbor Laboratory. Where it is regarded as a holy place for life sciences, she has planted a cornfield.

Qu Gaohewi

There is no doubt that 1944 was a crucial year in McClintock ’s career. She was elected as an academician of the American Academy of Sciences, and then as president of the American Society of Genetics (a position that has never been held by women), and she has been recognized by the public as the backbone of the genetics community. She was 42 years old that year.

On the occasion of his brilliant achievements, McClintock began the research that turned out to be the most important research in his life-the study of transposition. However, this research is far beyond time and space.
 
According to the existing research at that time, genes were fixed on chromosomes. They had a certain position, distance and order. They could only change their relative positions through exchange and recombination, and their relative properties through mutations.
 
However, through research, McClintock found that genes can move positions on chromosomes to "transpose" or "jump". This was simply unimaginable by geneticists at the time. This was also destined to be very cold when McClintock introduced the research he spent six years of hard work to the scientific community at the Summer Symposium in Cold Spring Harbor in 1951, and some geneticists even regarded it as "crazy" ".
 
Although not understood, McClintock did not change his original intention and insisted on her findings. In the discussion meeting five years later, she once again introduced her research findings, and the result was more ruthless ridicule and criticism.
 
People began to look at this once-prestigious female scientist with suspicion, her prestige fell from the brilliance of the apex, she was abandoned by the genetics community. Most of my friends and colleagues are gradually estranged, and McClintock has almost become an orphan, suffering from the longest loneliness and depression in his life.
 
In the early 1960s, French scientists Jacob and Mono used E. coli as an experiment and proposed a lactose operon model, which revealed the mechanism of gene regulation in organisms. This is a great encouragement to McClintock. She believes that the lactose operon model is too similar to her regulatory system, and she wrote a paper "Comparison of Corn and Bacterial Gene Control Systems" for this purpose, in order to attract the attention of the scientific community.
 
However, the scientific community quickly accepted the doctrines of Jacob and Mono, both of whom won the Nobel Prize in 1965, but the scientific community still ignored McClintock's "jumping gene" and still regarded her and her Theory is regarded as alternative and heresy.
 
Since then, McClintock began to exercise restraint and silence, no longer talk about his findings, and seldom publish related articles, but silently immersed himself in the research of corn genetics.
 
Shou Deyun sees the moon
 
With the further development of molecular biology and molecular genetics, scientists have gradually discovered many of the same or similar phenomena as McClintock's "jumping gene" in bacteria, fungi and other higher animals and plants.
 
For example, in 1966, biologists discovered in F. coli that F factors that can be integrated on the chromosome or can be extrachromosomal; in the late 1960s, biologists discovered the existence of so-called "insertion" Sequence "(IS) ...
 
This series of discoveries made people have to reexamine McClintock's research in corn. Her scientific discoveries beyond the times and her unyielding willpower surprised scientists.
 
In 1976, at the Symposium on "DNA Insertion Factors, Plasmids, and Epigenes" held by the Cold Spring Harbor Laboratory in the United States, the scientific community clearly recognized that the term "jumping gene" of McLintoque could be used to describe all DNA fragments that can be inserted into the genome. .
 
In 1983, the Nobel Prize Evaluation Committee of the Royal Swedish Academy of Sciences finally awarded the 81-year-old female scientist the physiology and medicine award of the year. "Without being understood by contemporaries, I completed the research work alone," the Nobel Prize jury commented.
 
In the face of the late recognition of the scientific community, McClintock was very indifferent,If you think you are taking the right step and have mastered the specialized knowledge, then no one can obstruct you. Don't pay attention to people's Difficulties and criticism. 

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