Figure 1

Experimental setup and tiling array intensity distributions. A: Schematics of embryos at the three stages of limb development (E11.5, E13.5 and E15.5) considered in this study. Forelimbs are indicated with a color code that is used in subsequent figures. The bars below the embryos indicate relative size differences. B: Histogram showing the intensity distributions along chromosome 2 for intergenic, intronic and exonic transcription. Exons considered are as defined in UCSC Known Genes annotation. C: Distribution of probe intensity around expressed genes on chromosome 2. TSS: transcription start site; PAS: polyadenylation site. Vertical gray dotted line: determined threshold level (in this example log2 = 7.554).