Karyotyping and Data Interpretation

Abstract

Research on human cytogenetics began with the work of Arnold (1879) and Fleming (1882) who for the first time examined human mitotic chromosomes. The detailed study of human chromosome morphology began 1956 after Tijo and Levan improved the technique of squash preparation using hypotonic shock and added colchicine to arrest cells in metaphase in order to increase the number of countable cells (Vogel and Motulsky, 1986). In their now classic article they reported that the human chromosome number was 46 and not 48 as was believed from earlier reports. Their work was confirmed in the same year by Ford and Hamerton (1956). The two articles stimulated a renewed interest in human cytogenetics and soon several laboratories were engaged in the study of human chromosomes and a variety of classification and nomenclature systems were proposed. This resulted in confusion in the literature and a need to establish a common system of nomenclature that would improve communication between workers in the field (Harnden, 1985). 1960 “A proposed standard system of nomenclature of human mitotic chromosomes“ was reported by a study-group which convened in Denver, Colorado. This report, more usually known as the Denver Conference (1960), has formed the basis for all subsequent nomenclature reports. The present human chromosome nomenclature (ISCN 1995) is based on the results of the following international conferences: Denver 1960, London 1963, Chicago 1966, Paris 1971, Paris 1975, Stockholm 1977, Paris 1981, Memphis 1994.