Human cells in suspension 3. The effect of in vitro aging on metaphase chromosome contraction in human lymphoid cells.

After differential staining of sister chromatids, chromosome length distribution and average chromosome length were determined for human lymphoid cells in, respectively, the first, second, third, and fourth and later mitoses. A significant change in chromosome length distribution and a marked decrease in average chromosome length were found for cells in the fourth and later mitoses. This supports previous suggestions that the observed changes in these parameters in cell population during in vitro aging are due solely to an increase of cells in the fourth and later mitoses.