Hose in Hose is caused by a retrotransposon insertion in the promoter of PvGlo. (A) Structure of wild-type (GenBank accession no. DQ381430) and Hose in Hose alleles (GenBank accession no. DQ38144) of PvGlo. The 1373-bp sequence upstream of the translation initiation codon (ATG) is bisected into regions upstream (650 bp) and downstream (723 bp) of the transposon insertion site (vertical arrow). The 2-bp target site duplication (GT) and the 10-bp motif AGCAATTTTA (stippled) in the native promoter and present in both long terminal repeats (LTR, hatched) of the 5381-bp retrotransposon (GenBank accession no. DQ381432) (thick line) are shown together with PCR primers. (B) PCR analysis of DNA from wild-type (WT), homozygous Hose in Hose (HH), and heterozygous Hose in Hose (Hh) plants. (C) Agarose gel electrophoresis of PCR products from Whorl 1 only and combined whorl 2, 3, and 4 tissue of revertant (R), semirevertant (SR), and Hose in Hose flowers (H) alongside a no-DNA control (-ve). DNA from leaves of the crowns producing semirevertant and revertant (R) and Hose in Hose (H) flowers was also amplified with primers as shown. (D) Revertant allele structure derived from sequence analysis (GenBank accession no. FJ897502) of PCR products from C, showing deletion (ΔGlo) after retrotransposon excision. Labels are as in A.