Joe Hin Tjio

from Wikipedia, the free encyclopedia
Joe Hin Tjio (undated)

Joe Hin Tjio (born November 2, 1919 in Java , † November 27, 2001 in Gaithersburg ) was a cytogeneticist who published the correct number of 46 chromosomes in a diploid chromosome set of human cells in 1956 . Knowing the correct number of chromosomes enabled cytogenetic research into the diseases associated with numerical chromosome aberrations .

Life

Tjio was born in 1919 to parents of Chinese origin in Java , which was then a Dutch colony . His father was a photographer. In 1940 he completed his training at the agricultural college in Bogor and then worked in plant breeding. In 1942, with the Japanese occupation of the Dutch East Indies during World War II , Tjio was interned by the Japanese . He was tortured during his three-year detention. These traumatic experiences in his younger years had a lasting impact on him, according to statements by later biographers. He was later described as a loyal and reliable friend, but also as a sensitive and easily ailable personality who easily came into conflict with authorities.

After the end of the war, he came to the Netherlands on a refugee ship of the International Red Cross , where a scholarship enabled him to continue his studies. During this time he also worked for half a year at the Royal Danish Academy of Sciences in Copenhagen . 1946 Tjio came to Sweden, where he at first at Lund located Svalöv carried out on plants cytogenetic studies. His research earned him a job as director of the institute in Saragossa , where he worked from 1948 to 1959. During this time, Tjio stayed regularly at the Institute of Genetics at Lund University , where he worked with Albert Levan and made his discovery in 1955 about human chromosome numbers.

In 1956, during a congress , Hermann Joseph Muller suggested Tjio to continue his research in the United States . Tjio was initially opposed to this possibility due to the political climate of the McCarthy era , but was later persuaded by Muller. In 1957 he moved to the Department of Biophysics at the University of Colorado Denver , which was headed by Theodore Puck . His research on the human chromosome set should be the basis of a doctoral thesis. In 1960 Tjio received the Ph.D. From 1959 Joe Hin Tjio did research at the National Institutes of Health (Laboratory for Experimental Pathology at the then National Institute of Arthritis and Metabolic Diseases ) in Bethesda . He retired in 1992 but continued to work in his laboratory until 1997. From 1997 until his death on November 27, 2001, Tjio lived in Gaithersburg .

Joe Hin Tjio was married to the Icelander Inga Bíldsfell (1919–2005) from 1948 and was the father of a son.

Act

In the 1950s it was assumed that the diploid human chromosome set consists of 2n = 48 chromosomes. In 1923 Theophilus Painter - despite certain doubts - assumed 48 chromosomes and his publication laid the basis for this number of chromosomes to find its way into the scientific literature over the next few decades.

Joe Hin Tjio, who worked in plant genetics until the 1950s, came into contact with the cytogenetics of human cells through research on the chromosomes of cancer cells at Albert Levan's laboratory in Lund. In the early morning hours of December 22, 1955, he observed 46 chromosomes in a preparation of embryonic human fibroblasts .

At the Institute for Genetics in Lund, Eva and Yngve Melander discovered a 46XY karyotype in their preparations of human liver cells in 1954, but - from the perspective of the time - did not follow up on this abnormality.

Tjio's results were published in April 1956 in the journal Hereditas . The journal was published by the Mendelian Society of Lund and had little circulation. In total, the chromosomes of 265 cells were counted, only four cells deviated from the described karyogram.

"Before a renewed, careful control has been made of the chromosome number in spermatogonial mitoses of man we do not wish to generalize our present findings into a statement that the chromosome number of man is 2n = 46 , but it is hard to avoid the conclusion that this would be the most natural explanation of our observations. "

"As long as the chromosome number in human spermatogonia mitoses has not been carefully checked again, we do not want to generalize our present observations by saying that the number of chromosomes in humans is 2n = 46 , although it is difficult to avoid the conclusion that this would be the most obvious explanation of our observation. "

- The chromosome number of man

Tjio was named as the main author of the publication, and Levan was the second author. According to Harper, there were disagreements between Tjio and Levan regarding first authorship, the main reason being that Tjio's discovery was made within Levan's research program, which was also responsible for its design, material and funding and therefore wanted to be the first author of the publication. According to laboratory staff, the publication was drafted in the style of Levan. A few years before his death, Tjio said that he had refused Levan the first authorship because Levan was not involved in the work and the process had hurt him deeply.

The basis of the experiment were various methods that had been developed in previous years, including the use of colchicine as a mitosis inhibitor introduced by Levan and the pretreatment of chromosomes with hypotonic solution described by TC Hsu .

Tjio presented his observations at the International Congress of Human Genetics , which first took place in Copenhagen in 1956 . The findings were confirmed in the same year by a paper by Charles E. Ford and John A. Hamertons in the journal Nature .

In Theodore Puck's laboratory in Denver, Tjio repeated the experiment with almost 2000 cells from 13 individuals and was able to confirm the results again. In the same work, the chromosomes were characterized based on their length and the position of the centromere.

Knowing the correct number of chromosomes enabled cytogenetic research into the diseases associated with numerical chromosome aberrations . Tjio's other scientific work was devoted to research on intellectual disability and leukemia . For his work in the former field, he was awarded a prize from the Joseph P. Kennedy, Jr. Foundation by US President John F. Kennedy in 1962 .

Publications (selection)

  • Joe H. Tijo, Albert Levan: The chromosome number of man. In: Hereditas . No. 42, 1956, pp. 1-6.

literature

Web links

Commons : Joe Hin Tjio  - Collection of pictures, videos and audio files

Individual evidence

  1. ^ A b Wolfgang Saxon: Joe Hin Tjio, 82; Research Biologist Counted Chromosomes . In: The New York Times . December 7, 2001.
  2. ^ A b Peter S. Harper: The discovery of the human chromosome number in Lund, 1955-1956. In: Human genetics . tape 119 , no. 1–2 , March 2006, pp. 226–232 , doi : 10.1007 / s00439-005-0121-x , PMID 16463025 (English, genmedhist.info online ).
  3. ↑ a b c d e f Rich McManus: Photographer, Prisoner, Polyglot - NIDDK's Tjio Ends Distinguished Scientific Career . ( Memento of April 15, 2012 in the Internet Archive ) In: NIH Record. November 2, 1997.
  4. ^ Theodor Puck: Living history biography. In: American journal of medical genetics. Volume 53, Number 3, November 1994, p. 280. doi: 10.1002 / ajmg.1320530313 , PMID 7856664 .
  5. ↑ Inga Tjio, 85, geneticist's wife . In: The Washington Times . July 30, 2005.
  6. ↑ Kesara Anamthawat-Jónsson: Inga Bíldsfell Tjio and Joe Hin Tjio . In: Morgunbladid. November 5, 2005 (with photo of the couple)
  7. ^ Theophilus Painter: Studies in mammalian spermatogenesis II: The spermatogenesis of man. In: Journal of Experimental Zoology. Number 23, 1923, pp. 291-336.
  8. ^ Stanley M. Gartler: The chromosome number in humans: a brief history. In: Nature Reviews Genetics. 7, 2006, pp. 655-660, doi: 10.1038 / nrg1917 .
  9. ^ A b c Peter S. Harper: The discovery of the human chromosome number in Lund, 1955-1956. In: Human genetics. Volume 119, number 1-2, March 2006, p. 228, doi: 10.1007 / s00439-005-0121-x , PMID 16463025 , genmedhist.info (PDF).
  10. ↑ Peter S. Harper: The discovery of the human chromosome number in Lund, 1955-1956. In: Human genetics. Volume 119, number 1-2, March 2006, p. 229, doi: 10.1007 / s00439-005-0121-x , PMID 16463025 , genmedhist.info (PDF).
  11. ^ Joe H. Tijo, Albert Levan: The chromosome number of man. In: Hereditas . No. 42, 1956, pp. 1-6.
  12. ↑ Peter S. Harper: The discovery of the human chromosome number in Lund, 1955-1956. In: Human genetics. Volume 119, number 1-2, March 2006, p. 230, doi: 10.1007 / s00439-005-0121-x , PMID 16463025 , genmedhist.info (PDF).
  13. ^ Albert Levan: The effect of colchicine on root mitoses in allium. In: Hereditas. 24, 1938, pp. 471-486, doi: 10.1111 / j.1601-5223.1938.tb03221.x .
  14. ↑ TC Hsu, CM Pomerat: Mammalian chromosomes in vitro: II. A method for spreading the chromosomes of cells in tissue culture. In: Journal of Heredity . 44, 1953, pp. 23-30.
  15. ^ Charles E. Ford, John A. Hamerton: The chromosomes of man. In: Nature. Volume 178, Number 4541, November 1956, pp. 1020-1023, ISSN  0028-0836 . PMID 13378517 .
  16. ↑ Joe H. Tjio, Theodore T. Puck: The somatic chromosomes of man. In: Proceedings of the National Academy of Sciences . Volume 44, Number 12, December 1958, pp. 1229-1237, ISSN  0027-8424 . PMID 16590337 . PMC 528712 (free full text).
  17. ↑ Peter S. Harper: The discovery of the human chromosome number in Lund, 1955-1956. In: Human genetics. Volume 119, number 1-2, March 2006, p. 231, doi: 10.1007 / s00439-005-0121-x , PMID 16463025 , genmedhist.info (PDF).
personal data
SURNAME Tjio, Joe Hin
BRIEF DESCRIPTION Cytogeneticists
DATE OF BIRTH November 2, 1919
PLACE OF BIRTH Java
DATE OF DEATH November 27, 2001
Place of death Gaithersburg