Schematic view of (a) B6 and (b) S7 Mup clusters. The tiling path of BAC clones is indicated by black lines with accession numbers listed. Predicted genes are represented by triangles, pseudogenes by rectangles. Predicted genes are numbered from the 5' direction independently in both strains; official names acquired by certain Mups based on cDNA sequences are listed as appropriate. Pseudogenes are listed alphabetically. Open triangles within the S7 sequence represent gene loci with CDSs that differ from their B6 counterparts, or in the case of gene 5 have no equivalent locus. The gray background shading within the center of each cluster contains those B6 genes and pseudogenes (and S7 equivalents) that form distinct clades within the phylogenetic analysis presented in Figure 2; the loci within the unshaded peripheral regions form isolated nodes. The calculated weight of the mature protein derived from each gene in B6 is indicated, with masses of non-equivalent S7 genes also being listed. Masses that correspond to mass spectrometry peaks identified in Figure 5 are highlighted in bold. The protein corresponding to B6 gene 18 has been identified by other methods (Figure 6); we predict that the calculated mass of the protein does not reflect the urinary mass due to the occurrence of glycosylation (see Results). B6 gene 11 matches closely to an additional protein mass we have previously identified in fractionated urine  (see Results). There are three non-equivalent sequence gaps within the central regions of both B6 and S7; the ordering of the central contigs presented here is arbitrary. The S7 genomic sequence includes the Tscot and Zfp37 loci, which flank the cluster in B6 (not shown), indicating that the start and end of the cluster are present. Ignoring gap regions, the B6 cluster is 1.56 Mb in size, the S7 cluster 0.72 Mb.