Joe Hin Tjio
Encyclopedia
Joe Hin Tjio was a cytogeneticist renowned as the first person to recognize the normal number of human chromosome
s. This epochal event occurred on December 22, 1955 at the Institute of Genetics of the University of Lund in Sweden
, where Tjio was a visiting scientist.
, then part of the Dutch East Indies
. His father was a photographer. Tjio was educated in Dutch colonial schools, trained in agronomy
in college, and did research on potato breeding. He was imprisoned for 3 years and tortured by the Japanese in a concentration camp during World War II
.
, whose government provided him with a fellowship for study in Europe. He worked in plant breeding in Denmark
, Spain
and Sweden. From 1948 to 1959 he did plant chromosome research in Zaragoza
in Spain and spent his summers and vacations in Sweden working with Professor Albert Levan
in Lund.
It was during one of his vacation stays in Lund that Tjio made his discovery of the correct human chromosome count. For fully a half century it had been accepted that humans normally have 48 chromosomes. Now Tjio knew "the chromosome number of man" was 46. Tjio's revolutionary finding was published (with Levan as his co-author) in the Scandinavian journal Hereditas on January 26, 1956, only a month and four days after the discovery.
In 1958 Tjio went to the United States
and in 1959 he joined the staff of the National Institutes of Health
in Bethesda, Maryland
. He received his Ph.D. in biophysics and cytogenetics from the University of Colorado
. He spent the balance of his long career at the NIH in human chromosome research. He was named scientist emeritus in 1992, but maintained a laboratory for the next five years. In 1997, he retired to Gaithersburg, Maryland
.
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s. This epochal event occurred on December 22, 1955 at the Institute of Genetics of the University of Lund in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, where Tjio was a visiting scientist.
Early life
Tjio (whose name is pronounced CHEE-oh) was born to Chinese parents in JavaJava
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
, then part of the Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....
. His father was a photographer. Tjio was educated in Dutch colonial schools, trained in agronomy
Agronomy
Agronomy is the science and technology of producing and using plants for food, fuel, feed, fiber, and reclamation. Agronomy encompasses work in the areas of plant genetics, plant physiology, meteorology, and soil science. Agronomy is the application of a combination of sciences like biology,...
in college, and did research on potato breeding. He was imprisoned for 3 years and tortured by the Japanese in a concentration camp during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
Career
After the war ended, Tjio went to the NetherlandsNetherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, whose government provided him with a fellowship for study in Europe. He worked in plant breeding in Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Sweden. From 1948 to 1959 he did plant chromosome research in Zaragoza
Zaragoza
Zaragoza , also called Saragossa in English, is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain...
in Spain and spent his summers and vacations in Sweden working with Professor Albert Levan
Albert Levan
Albert Levan was a Swedish botanist and geneticist.Albert Levan is best known today for co-authoring the report in 1956 that humans had forty-six chromosomes...
in Lund.
It was during one of his vacation stays in Lund that Tjio made his discovery of the correct human chromosome count. For fully a half century it had been accepted that humans normally have 48 chromosomes. Now Tjio knew "the chromosome number of man" was 46. Tjio's revolutionary finding was published (with Levan as his co-author) in the Scandinavian journal Hereditas on January 26, 1956, only a month and four days after the discovery.
In 1958 Tjio went to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and in 1959 he joined the staff of the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
in Bethesda, Maryland
Bethesda, Maryland
Bethesda is a census designated place in southern Montgomery County, Maryland, United States, just northwest of Washington, D.C. It takes its name from a local church, the Bethesda Meeting House , which in turn took its name from Jerusalem's Pool of Bethesda...
. He received his Ph.D. in biophysics and cytogenetics from the University of Colorado
University of Colorado
The University of Colorado system is a system of public universities in Colorado consisting of three universities in four campuses: University of Colorado Boulder, University of Colorado Colorado Springs, and University of Colorado Denver in downtown Denver and at the Anschutz Medical Campus in...
. He spent the balance of his long career at the NIH in human chromosome research. He was named scientist emeritus in 1992, but maintained a laboratory for the next five years. In 1997, he retired to Gaithersburg, Maryland
Gaithersburg, Maryland
Gaithersburg is a city in Montgomery County, Maryland, United States. The city had a population of 59,933 at the 2010 census, making it the fourth largest incorporated city in the state, behind Baltimore, Frederick, and Rockville...
.
External links
- Human chromosome count in MedTerms Medical Dictionary