A computer based videodensitometric system for studying banded human chromosomes illustrated by the analysis of the normal morphology of chromosome 18

A computer based, high resolution, high speed system is described for the digitization of television images of human G banded chromosomes, on line directly from a microscope. The digitized data are processed by a computer to determine the total length and centromere index of individual chromosomes and to obtain an integrated density profile representing the band pattern. The density profile is reduced by the computer to a series of dark and light bands, each with a defined position, width, and density. The results are displayed by the computer on a television monitoring a form that simulates routine laboratory preparations and that allows cytogenetic inspection. The system is easy to operate, and it includes a wide range of options for operator interaction to ensure reliability. The results of the computer analysis of the no. 18 chromosomes from 5 cells from each of 10 different persons demonstrated the usefulness of the system for detecting, measuring, and analyzing individual bands in human populations and its application to establishing band patterns of chromosomes in different states of contraction.