Fig. 2. Reduced stringency Southern blot analysis to estimate AP-2 gene number in the amphioxus and lamprey genomes. (A) Genomic DNA from five individual adult amphioxus was digested with four restriction enzymes and analyzed on the same Southern blot. Lanes from three representative individuals are shown. Interestingly, each animal gives a different banding pattern. For a particular enzyme, an individual has no more than two band types, and most of these bands are shared between individuals. For example, individuals 2 and 3 share lowest ClaI band, while all three individuals share a single ApaI band. Overall, the banding patterns are most consistent with various hetero- and homozygotic combinations of restriction fragment length polymorphisms at a single locus, suggesting there is one amphioxus AP-2 gene. (B) Genomic DNA from a single adult lamprey digested with five restriction enzymes. Four out of five digests yield a single band, consistent with there being a single lamprey AP-2 gene. A, ApaI; C, ClaI; V, EcoRV; H, HindIII; E, EcoRI; N, NcoI; P, PstI; S, StuI.