Figure 2.

The heptamer is active when moved to new locations within the ade6 gene. (A) The original M26 heptamer. (B) The heptamer moved 57 bp downstream of M26 (+57 Heptamer; ade6-3001). (C) The heptamer moved 747 bp downstream of M26 (+747 Heptamer; ade6-3002). Each heptamer allele was crossed with a series of test alleles, and the recombinant frequency (determined as the number of Ade⁺ spores per 10⁶ viable spores) is plotted against the position of the test allele along the ade6 gene. The open rectangle indicates the coding region of ade6 (Fig. 1). Closed symbols represent heptamer mutations, and open symbols indicate control strains that contain the same number and type of base changes without creating the heptamer. The arrow indicates the position of the heptamer sequence.