Figure 2.—

Genetic scheme II used to identify novel Ac excision alleles. (A) Genetic strategy developed to recover ps1 footprint alleles. Triangles represent Ac insertions. “+” represents the wild-type allele. Large parentheses represent putative excision alleles. Ac excision events are indicated by curved arrows. Solid arrows denote primers designed to amplify the donor Ac (dAc, bti97156∷Ac). Shaded angled arrows represent primers designed to amplify the Ac insertion site at ps1 locus. (B) A representative PCR gel image. When Ac is present, Ac-specific and locus-specific primers result in amplification products of a predicted size. If Ac is absent from the locus, no products are detected. The 1-kb DNA ladder (Promega) is labeled as M. Eight individual plants were genotyped using two PCR reactions. Odd-numbered lanes show products that result from amplification of the dAc (lanes 1, 5, 9, 13, and 15), whereas even-numbered lanes show expected products when Ac is inserted at the ps1 locus (lanes 2, 4, 8, 10, and 14). Lanes without amplification products indicate a potential Ac excision allele.