Figure 5.

There is no single gene in the parental strain (C57BL/6) genome that could have given rise to the bm28 mutation. We probed the B6 genome for genes that might contain both halves of the bm28 mutation cluster. Genomic DNA from bm28 mice and B6 mice was digested with one of three endonucleases, size-separated, then hybridized to probe D^bm28-97/99–2 (left blot in each pair) or to probe D^bm28-103 (right blot in each pair). Any fragment that contains a gene with the entire mutation cluster would have a consistent size when hybridized to either the left- or right-half probe; however, the only fragment with this property is the fragment containing the D^bm28 gene (marked by arrows).