The discovery of the human chromosome number in Lund, 1955-1956

• Published in: Human genetics 2006-03, Vol.119 (1-2), p.226-232
• Main Author: HARPER, Peter S
• Format: Article
• Language: English
• Subjects: Albert Levan; Biological and medical sciences; Chromosome Disorders - diagnosis; Chromosome Disorders - genetics; Chromosomes, Human - genetics; Classical genetics, quantitative genetics, hybrids; Cytogenetic Analysis - history; Cytogenetic Analysis - methods; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Genetics, Medical - history; History, 20th Century; Human; Humans; Joe-Hin Tjio; Karyotyping; Levan; Sweden; Tjio
• ISSN: 0340-6717; 1432-1203
• DOI: 10.1007/s00439-005-0121-x

The correct determination of the human diploid chromosome number as 46, by J-H Tjio and A Levan, at the University of Lund, Sweden, occurred 50 years ago, in December 1955; the finding was published in April 1956, ending a period of more than 30 years when the number had been thought to be 48. The background to the discovery and the surrounding factors are reassessed, as are the reasons why previous investigators persistently misidentified the precise number. The necessity for multiple technological advances, the power of previously accepted conclusions in influencing the interpretation of later results, and the importance of other work already undertaken in Lund, are all relevant factors for the occurrence of this discovery, the foundation for modern human cytogenetics, at this particular time and place.