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Gene expression can be silenced by proximity to heterochromatin blocks containing centromeric α-satellite DNA. This has been shown experimentally through cis-acting chromosome rearrangements resulting in linear genomic proximity, or throughtrans-acting changes resulting in intranuclear spatial proximity. Although it has long been been established that centromeres are nonrandomly distributed during interphase, little is known of what determines the three-dimensional organization of these silencing domains in the nucleus. Here, we propose a model that predicts the intranuclear positioning of centromeric heterochromatin for each individual chromosome. With the use of fluorescence in situ hybridization and confocal microscopy, we show that the distribution of centromeric α-satellite DNA in human lymphoid cells synchronized at G₀/G₁ is unique for most individual chromosomes. Regression analysis reveals a …