caption death_date birth_place image_size nationality field birth_date known_for prizes article_title name alma_mater
torbjörn caspersson 7 december 1997 motala 150px swedish cytologist geneticist . 15 october 1910 nucleic acids balzan 1988 -rrb- prize -lrb- 1979 -rrb- william allan award -lrb- torbjörn caspersson
 torbjörn caspersson university of stockholm ,
torbjörn caspersson

professor torbjörn oskar caspersson -lrb- 15 october 1910 -- 7 december 1997 -rrb- was a swedish cytologist and geneticist .
he was born in motala and attended the university of stockholm , where he studied medicine and biophysics .
caspersson made several key contributions to biology .
in the 1934 he and einar hammarsten showed that dna was a polymer .
previous theories suggested that each molecule was only ten nucleotides long .
he provided william astbury with well prepared samples of dna for astbury 's pioneering structural measurements .
in 1936 , in his doctoral thesis in chemistry , presented at the karolinska institute in stockholm , he first studied genetic material inside a cell with an ultraviolet microscope to determine the nucleic acid content of cellular structures such as the nucleus and nucleolus using the feulgen reaction to stain the dna .
he worked with jack schultz in stockholm from 1937 -- 1939 on protein synthesis is cells and published the work in 1939 , where he independent of jean brachet , working out the same problem using a different technique , found that cells making proteins are rich in ribonucleic acids rna , implying that rna is required to make proteins .
this was summarised in his book ` cell growth and cell function ' -lrb- 1950 -rrb- .
he received a personal professorship from the swedish state in 1944 .
he became head of the newly created department for cell research and genetics at the medical nobel institute , at the karolinska , in 1945 .
he was the first study the giant chromosomes found in insect larvae .
he studied the role of the nucleolus in protein synthesis .
he examined the relationship between the quantity of heterochromatin -lrb- chromosomes with few genes -rrb- and the rate of growth of cancer cells .
in 1969 when working at the karolinska institute , he -lrb- with lore zech -rrb- found that a stain -lrb- quinacrine mustard -rrb- caused chromosomes to show light and dark lateral bands along their length .
this banding method permits the accurate identification of all 22 autosomes and the x and y chromosomes .
this technique highlighted slight structural abnormalities and specific identification of the extra chromosomes involved in conditions such as down 's syndrome -lrb- see also cytogenetics -rrb- .
in 1977 he retired as head of the medical cell research and genetics department at the karolinska institute in stockholm in 1979 caspersson was awarded the balzan prize for biology `` for his fundamental studies on protein metabolism and nucleic acids , culminating in a method for identifying specific bands on individual chromosomes by ultraviolet microscopy , thereby creating a new tool for the study of evolution '' -lrb- motivation of the balzan general prize committee -rrb- .
