In the interphase nucleus, each chromosome occupies a discrete chromosome
territory,
and is separated from other chromosomes by an interchromosomal domain,
where much transcription activity occurs.
Euchromatin (open, frequently transcribed) replicates in early S phase, heterochromatin replicates in late S phase.
Channels between chromosomes are called interchromosomal compartments.
Chromosome structure is continuously rearranged so that transcriptionally active genes are cycled to the edges of chromosome territories.