Tissue-specific relative positioning of chromosomes 12, 14 and 15. Quantitation of triplet cluster formation by determining for each tissue type the percentage of cells containing (a) no 12-14-15 triplet clusters, (b) a single triplet cluster of exactly one chromosome 12, 14 and 15, (c) a single cluster of a pair of homologues and one additional chromosome, or (d) a cluster of homologues and more than one additional chromosome. Expected values based on random distribution of chromosomes are indicated by a dashed line. Between 41 and 180 cells were analyzed per tissue. (e) FISH analysis of different cell types for chromosome 12 (red), 14 (blue), and 15 (green). Distinct preferential cluster types are found in different cell types. Scale bar, 1.8 μm.