If sex chromosomes differ sufficiently in size (and hence in DNA content), or in DNA base composition, flow cytometric analysis of isolated nuclei may be used for early screening of sex in non-flowering individuals.
Figure 23. Histogram of relative nuclear DNA content obtained after simultaneous analysis of nuclei isolated from male (M, 2n = 24, XY) and female (F, 2n = 24, XX) plant of Melandrium album. Compared to the X chromosome, the Y chromosome has approximately two times higher DNA content. Thus, the G1 and the G2 peaks corresponding to both sexes are clearly separated
