For C-banding, immersion oil was removed from the slides
with xylene and alcohol, and the slides then allowed to dry. Two-
day old slides were treated with saturated barium hydroxide at
room temperature, rinsed in three changes of distilled water at pH
6.8, and incubated in salt-sodium citrate (0.3M sodium chloride
and 0.03M trisodium citrate in unbuffered distilled water) for 1 h
at 55 C. The length of the treatment in barium hydroxide is
temperature dependent. At temperatures of about 23 C a 5-min
treatment was normally effective, but at 18e20 C, 8 or even 12min
were needed. One of the advantages of this protocol is that it allows
the same individual preparations to be photographed plain and
then C-banded.