Organization of the LCR22-2 locus. We show a 128-kb-long segment homologous to LCR22-4. The locus contains one functional gene, USP18. There is a predicted gene, XM_092877, but it is not expressed (M. Babcock and B.E. Morrow, unpubl.), and many pseudogenes. The region contains three ∼35-kb-long duplications denoted dupA, dupB, and dupC (these correspond to the red blocks in Babcock et al. 2003). dupA starts in the 3′ part of the USP18 gene. USP18 introns are marked in blue, coding exons in red; the first noncoding exon is highlighted in yellow. dupB and dupC contain the 3′ part of the last internal intron, last exon, and 3′-UTR of USP18. The bottom part shows the exact localization of LCR22-2 and the region homologous to LCR22-4. The LCR22-4 homology corresponds to a segment defined by dupB and dupC.
