Differential frequency of human X and Y chromatin as related to cell density in vitro.

The relationship between cell density in vitro and the frequency of fluorescent X chromatin and/or Y chromatin-positive interphase nuclei was studied in cultured cells from three human male and female subjects. It was found that altough the frequency of fluorescent X chromatin-positive cells was proportional to cell density, the frequency of fluorescent Y chromatin-postitive cells was independent of cell density. Our results are compared with those of other investigators.