Figure 1.

Distribution of crossover sites after one yeast generation in brome mosaic virus (BMV) RNA3. Single lines represent non-coding regions, and labeled boxes represent 3a, URA3, the template recruitment element (RE), the subgenomic RNA4 promoter (SG), and the 3′ tRNA-like sequence (TLS). (A) Recombination partners B3Δ5′ and B3Δ3′pm are non-replicatable, overlapping (~618 nt) B3URA3 derivatives transcribed in vivo from plasmids carrying the CUP1 or GAL1 promoter, respectively. In B3Δ5′ the 5′UTR and the 5′ half of 3a was replaced by the GAL1 leader sequence. B3Δ3′pm harbored point mutations and its 3′end is formed by the ADH1 polyadenylation signal (An). A probe against 5′3a sequences was used to detect intermolecular recombinants; (B) The number and frequency (%) of recombinants formed between point mutations. Forty-two RNA recombinants randomly selected from three biological replicates were sequenced; (C) Frequency of intermolecular RNA recombination between B3Δ5′ and B3Δ3′ or B3Δ3′pm. Bars represent the average and standard error of three replicates. In parenthesis is the total number of cases observed. The average sample size per treatment was 210,000 cells.