Figure 2.A "flow karyotype" of a wheat cell line. The
continuous trace is
a frequency distribution histogram showing the number of chromosomes with
each particular fluorescence. The five sharp peaks correspond to single
chromsomes or pairs of chromosomes, while the smoother curves are formed
where many individual chromosome types are not resolved (right), or from
broken chromosomes, nuclei, or organelles (left). This graph is derived
from a two-wavelength analysis, shown as the diagonal line where density
of dots is proportional to number of chromosomes detected of each
fluorescence. Some peaks on the continuous line are now resolved as two
peaks (arrow). The karyotype is derived from analysis of 50, 000
chromosomes, taking about 5 minutes. I thank Nigel Miller at the
Babraham Institute, Cambridge, for assistance in operating the flow cylinder.
Click on image for a slightly larger version.