Southern blot analysis of NotI-containing regions of the 5′-ETS and 28S. (a) Fragment sizes generated by digestion of genomic DNA with BamHI (B) and NotI (N) in the 5′-ETS region are illustrated above. Genomic DNA from spermatozoa and liver was digested with BamHI only in lanes 1 and 4, respectively. Both BamHI and NotI were used to digest spermatozoa DNA from young and old animals in lanes 2 and 3, respectively, and liver DNA from young and old animals in lanes 5 and 6, respectively. (b) Fragment sizes generated by digestion of genomic DNA with EcoRI (RI) and NotI (N) in the 28S region are illustrated. The identical arrangement of enzyme digestions, tissues, and ages used in a were applied to the 28S region except for the replacement of BamHI with EcoRI.