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Section 2:Fruit Fly and Mouse

The method of locking up your stuff until you have published about it, or of keeping secret your ideas and progress have never appealed to me personally. It may be, that we can claim no special virtue here, for Drosophila is like the air we breathe—there is enough for all. 

Thomas Morgan to Robert S. Woodward, July 25, 1917.

Gregor Johann Mendel(1822-1884)


Thomas Morgan was born on 25 September 1866(the year Mendel published his famous paper) in Lexington, Kentucky. Morgan developed a special interest in fossils in the Kentucky mountains when he was a young man. Morgan received his BS degree from the University of Kentucky and received his PhD at Johns Hopkins University in 1890.

In 1904, Morgan and his wife Lilian Vaughan Morgan(1870-1952) moved to Columbia University,where Morgan was appointed professor of experimental zoology. The fruit fly Drosophila melanogaster was introduced into his lab at Columbia University in 1908. He studied Drosophila melanogaster over the following years, making it the most famous model organism for genetic studies. Morgan was the first person to definitively link the inheritance of a specific trait with a particular chromosome.

In 1910, Morgan started to hire undergraduates to work on Drosophila in the “fly room” where they remained for the next seventeen years. The main members include Calvin Bridges(1889-1938), Alfred Sturtevant(1891-1970),Otto Lous Mohr(1886-1967),Theodosius Dobzhansky(1900-1975),H. J. Muller(1890-1967)and Curt Stern(1902-1981). They showed that genes are linked in a series on chromosomes and developed the mechanism of crossing-over and the concept of genetic mapping.

In 1928 Morgan left Columbia to become professor of biology at the California Institute of Technology. He received the Nobel Prize for Physiology or Medicine in 1933“for his discoveries concerning the role played by the chromosome in heredity”. 
Morgan is widely recognized as one of the most influential biologists of the twentieth century. By guiding Chinese students including Chenzhen(1894-1957), Liruqi(1895-1991)and Tanjiazhen(1909-2008), he also had an important impact on Chinese genetics.


Huettner, Alfred F. (Alfred Francis), b. 1884, "T.H. Morgan in the "Fly Room" Columbia University c. 1916".

Embryo Project Encyclopedia (1916). ISSN: 1940-5030

Hermann Joseph Muller(1890-1967)


Hermann Joseph Muller was born on 21 December 1890 in New York City, New York. Muller  attended Columbia University from 1907 to 1909, where his interest in genetics was fired first by E.B. Wilson(1856-1939), a cytologist. From 1910 to 1915, Muller studied heredity and genetic mutations in the fruit fly (Drosophila) with the guidance of Thomas Morgan. Muller verified earlier theories that chromosomes are the physical components by which offspring inherit traits from their parents.
In 1920, Muller moved to the University of Texas, where he used x-rays in his experiments with fruit flies. He demonstrated that x-rays can mutate the structure of genetic material in 1927.


He then left the University of Texas for research jobs in Europe, and from 1934 to 1937, he was the senior geneticist at the Institute of Genetics of the Academy of Sciences in Moscow, USSR. Muller returned to the United States in 1940. He consulted on the Manhattan Project and provided advice on experiments pertaining to the mutational effects of radiation.

In 1946, Muller received a Nobel Prize in Physiology or Medicine for his 1927 work on radiation-induced genetic mutations. 

Chen Zhen(1894-1957)

Chen Zhen (1894-1957) is a famous zoologist and biological historian in China. He is also a geneticist and one of the founders of animal behavior in China. In 1914, he was admitted to Nanjing Jinling University and entered the newly established agricultural department of the University. In 1919, Chen Zhen obtained the qualification of Tsinghua University to study biology in the United States at public expense, went to Cornell University to study as a graduate student, and transferred to Columbia University in the spring of 1920 to study in the laboratory of E.B. Wilson. In 1921, he received a master's degree from Columbia University, and then studied genetics under Professor T.H.Morgan, an American geneticist. In 1928, Chen Zhen published "transparency and five flowers, the first Mendelian inheritance in goldfish" on genetics, which is the first work in the world to prove incomplete dominant inheritance of genes in goldfish.

In 1929, President Luo Jialun of Tsinghua University invited him to preside over the Department of biology of Tsinghua University. He had been the director of the Department of biology of Tsinghua University until 1952. In 1952, the departments of colleges and universities across the country were adjusted. The biology departments of Peking University, Yanjing University and Tsinghua University merged into the Biology Department of Peking University. Chen Zhen was changed to Professor and director of the Research Office of the Biology Department of Peking University. Chen Zhen was elected as an academician of the Central Academy of Sciences in 1948 and the first member of the Faculty of the Chinese Academy of Sciences in 1955.


Chen SC. Transparency and Mottling,

a Case of Mendelian Inheritance in the Goldfish CARASSIUS AURATUS. Genetics. 1928 Sep;13(5):434-52


Group photo of natural science teachers in Tsinghua School in 1925.

The first from the left in the front row is Chenzhen. 

Li Ruqi (1895-1991)


Born in Tianjin in 1895, Li Ruqi was admitted to Tsinghua preparatory school for studying in the United States in 1911, graduated in 1919, and studied at Purdue University in the United States from 1919 to 1923. After that, he entered the Research Institute of the Department of zoology of Columbia University and worked on his doctoral thesis under the guidance of T.H.Morgan and C.B. Bridges. In 1926, he received his doctoral degree with excellent results. In 1927, he published his paper "the effect of structural aberration of Drosophila chromosome on its development" in the Journal of genetics. After that, Li Ruqi returned to China to teach as an associate professor of Fudan University in Shanghai, Professor of Biology Department of Yanjing University, Professor of Peking University School of medicine, director of Department of zoology and director of pre Medical Department of Peking University, Professor of Department of biology and director of genetics teaching and Research Office of Peking University.

On April 29th, 1957, GuangMing Daily published an article by Li Ruqi, "talking about the contention of a hundred schools of thought from genetics". After reading it, Mao Zedong suggested that the people's daily reprint it, and personally changed the title of the article to "the only way to develop science", with the original title as the subtitle, and also wrote a note for it.

Tan Jiazhen (1909-2008)


In 1936, Tan Jiazhen and Morgan

Tan Jiazhen was born in Cixi, Ningbo, Zhejiang Province on September 15, 1909. In 1926, Tan Jiazhen was escorted to Soochow University to study biology. In 1930, Tan Jiazhen became a graduate student of Professor Li Ruqi of Yanjing University to carry out research on the genetic law of color spots of Asian ladybugs. With the help of Li Ruqi, in 1934, Tan Jiazhen went to California Institute of technology to study for a doctor's degree, studied under Morgan, the founder of modern genetics, and graduated with a doctor's degree in 1936. In the same year, he published the genetic map of Drosophila autosomes on genetics.


Tan Jiazhen returned to China in 1937 to teach in the Biology Department of Zhejiang University. After the Department was adjusted in 1952, he served as the director of the Biology Department of Fudan University. After the reform and opening up, Tan Jiazhen became active on the international academic stage again, promoted international academic exchanges, introduced advanced instruments, and promoted the development of molecular biology in China. In 1983, Tan Jiazhen was awarded the honorary Medal of "outstanding alumni" by the California Institute of technology, and was elected as a foreign academician of the American Academy of Sciences in 1985.

J. B. S. Haldane(1892-1964)


John Burdon Sanderson Haldane FRS (November 5, 1892 – December 1, 1964), was a British geneticist and evolutionary biologist. He was one of the founders of population genetics, along with Ronald Fisher (1890-1962) and Sewall Wright (1889-1988).

He was Son of the noted British physiologist John Scott Haldane (1860-1936) and began studying science as assistant to his father at the age of eight. Haldane received formal education in the classics at Eton College and at New College, Oxford. During the First World War, Haldane served in France and Iraq. After the war, Haldane worked as a fellow of New College, then moved to Cambridge and later University College, London.

Haldane’s work reestablished natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian genetics, known as the "modern evolutionary synthesis,".
Haldane’s essay in 1923, Daedalus, was remarkable in predicting many scientific advances. He coined the term "clone" in a speech entitled, "Biological Possibilities for the Human Species of the Next Ten-Thousand Years,"


In 1957 Haldane moved to India and died in 1964.

Frederick Griffith (1877-1941)

Frederick Griffith (1877–1941) was a British bacteriologist whose focus was the epidemiology and pathology of bacterial pneumonia. Griffith studied medicine at the University of Liverpool and later worked at the Pathological Laboratory of the Ministry of Health. He developed a reputation for his thorough and methodical research.


With support from the UK government, Griffith was sent pneumococci samples taken from patients throughout the country, amassed a large number, and would classify each pneumococci sample to search patterns of pneumonia epidemiology; he also experimented on mice for improved understanding of its pathology. The pivotal experiments — actually very many experiments — was performed during the 1920s. In January 1928 he reported what is now known as Griffith's Experiment, the first widely accepted demonstrations of bacterial transformation. 


Griffith Experiment in 1928 

Griffith's experiment, reported in 1928 by Frederick Griffith, was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation. 

Pneumonia was a serious cause of death in the wake of the post-WWI Spanish influenza pandemic, and Griffith was studying the possibility of creating a vaccine. Griffith used two strains of pneumococcus (Streptococcus pneumoniae) bacteria which infect mice – a type III-S (smooth) which was virulent, and a type II-R (rough) strain which was nonvirulent. The III-S strain synthesized a polysaccharide capsule that protected itself from the host's immune system, resulting in the death of the host, while the II-R strain did not have that protective capsule and was defeated by the host's immune system. 
In this experiment, bacteria from the III-S strain were killed by heat, and their remains were added to II-R strain bacteria. While neither alone harmed the mice, the combination was able to kill its host. Griffith was also able to isolate both live II-R and live III-S strains of pneumococcus from the blood of these dead mice. Griffith concluded that the type II-R had been "transformed" into the lethal III-S strain by a "transforming principle" that was somehow part of the dead III-S strain bacteria. 


He showed that Streptococcus pneumoniae, implicated in many cases of lobar pneumonia, could transform from one avirulent strain into a different, virulent strain. The observation was attributed to an unidentified underlaying principle, later known in the Avery laboratory as the "transforming principle" and identified as DNA.

The exact nature of the transforming principle (DNA) was later verified in the experiments done by Avery, McLeod and McCarty (published 1944) and by Hershey and Chase (1952).

Hand Operated Centrifuge, Circa 1930

Brass instrument with removable wooden handle. Holds two centrifuge tubes. Used for rapid settling of suspended solids

from small quantities of liquid in analytical or clinical procedures.

Manufactured by Charles Lentz & Sons and Bausch + Lomb.

Science History Institute. Hand Operated Centrifuge. Photograph, 2021.

Science History Institute. Philadelphia.


Klett Bio Colorimeter, 1929

Klett Bio Colorimeter, a device used in colorimetry to measure the absorbance of particular wavelengths of light by a specific solution. Colorimeters are commonly used to determine the concentration of a known solute in a given solution by the application of the Beer-Lambert law, which states that the concentration of a solute is proportional to the absorbance.

Klett Bio Colorimeters were specifically designed for clinical laboratory work. For example, they can be used to determine the concentration of hemoglobin, or other substances, in blood. This Klett colorimeter includes standard color disks made of glass, which can be used in place of standard solutions in color comparisons. The color disks are inserted into glass "plungers," similar to the glass sample cups, and viewed alongside the samples. The colorimeter's black metal base is attached to an upright made of hollow bronze and finished with black enamel which supports the microscope reader. Two stainless steel knobs on the upright control the height of the sample stand. The base supports a sliding metal and glass daylight filter and a blue glass color filter. The hollow base contains a light bulb and a hemoglobin results table, printed on linen, is built into the bottom front of the base and can be scrolled through with a black plastic knob.

Science History Institute. Klett Bio Colorimeter. Photograph, 2021. Science History Institute. Philadelphia.

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