mammalian chromosomes are not spread out the entire nucleus but take up a spatially limited area,their respective chromosome territory (33).In yeast,however,such territories are absent(121).As genetic loci can change their position in the nucleus by 1 um in several minutes (127),yeast nuclei are possibly too small to stably build up chromosome territories.The same,of course,is likely to apply to the trypanosome nucleus,which has not been extensively stuied in this context.