Automated measurements on human C-bands in family studies

An automated system providing quantitative measurements of C-band size has been used, in conjunction with statistical methodology developed for the purpose, in a family study to demonstrate its potential in determining the mode of transmission of C-bands from parent to offspring, and to test the assumption of Mendelian inheritance. The most serious obstacle encountered was the high within-person variance of the normalized band sizes, the large within-slide variance being increased by technical variation between different preparations. Attempts to reduce variance by developing more effective normalization techniques did not prove fruitful. Nevertheless, the ability of the present system to perform a trace using a reasonable number of cells has been demonstrated in an example. In the two families studied we saw no evidence that band size was not transmitted and changes in band size, if any, were less than about 5 micrometer2 X 10(-2) (compared to a typical medium-category band size of about 65 mcirometer2 X 10(-2)).