The fluorescence pattern of the human karyotype

The pattern of fluorescence of the 24 human chromosome types is described and illustrated by means of one karyotype (Fig. 1) and one idiogram (Fig. 2). The fluorescent bands are of two main types: those with dark shades (dark and dim), called negative, and those with light shades (light, bright and intense), called positive. The number, size and shade of the fluorescent bands are recorded and each band is located in the human idiogram. The locations are determined as distances from the centromere in each chromosome, the unit of distance being 1% of the female haploid chromosome length. A nomenclature is proposed, in which the bands are numbered from the centromere to the chromosome ends. Since the centromeric regions in all human chromosomes show negative fluorescence, it follows that negative bands will have 0 or even numbers and positive bands odd numbers. The survey of the morphological data resulted in the finding of some suggestive trends with possible bearing on karyotypic evolution in man.