The chromosomal organisation of the mouse (top) and human (bottom) α-globin clusters.

<p>The embryonic ζ gene in each locus is represented in yellow, the pseudogenes in purple, and the foetal/adult α genes in red boxes. The positions of DNase I hypersensitive sites, discussed in the text, are shown as arrows. The widely expressed gene <i>NPRL3</i> is transcribed from the opposite strand to that of α-globin and is shown as an orange box, with exons in black bars. Grey boxes refer to previously defined multispecies conserved elements (MCS), and light-green boxes indicate CpG islands. Note the lack of CpG islands in the mouse locus. The previously described natural (IJ, MC) and targeted (C40, ΔMCS-R2) deletions from the human and targeted deletions from the mouse (ΔP6, ΔP6-R3, and SND) α-globin cluster are shown as annotated.