Fig. 5.

An example, where distance measurements were made between three pairs of FISH probes. (A) Typical images of one nucleus obtained 30 min after stimulation, used for separation measurements. Bar: 2 μm (insets 500 nm, 90-nm pixels). (B) Occurrences given by multispectral 100-nm beads (where the expected separation is zero if channel registration and localization are perfect). (C) The separation (nm) seen between probe 2 (target 2 kbp downstream from the transcription start site) and probe 34 (target 34 kbp downstream). Histograms (30-nm bins) illustrate the number of times a separation was seen (occurrence). Gaussian distributions are fitted to histograms, and normalized by equalizing areas under curves to allow direct comparison of probabilities (circles indicate means). (D) The separation (nm) seen between probe 2 and probe 128 (target 128 kbp downstream). (E) The separation (nm) seen between probe 2 and probe 138 (target 138 kbp downstream).