Figure 3.

Model of the RNA structure for portions of the Adh transcript. (A) Secondary structure proposed for exon 2. Pairing regions are shown connected by straight lines. All pairing stems were determined by phylogenetic analysis (see Table 1). Note that this figure shows only the portion of exon 2 where the four conserved pairings were found. (B) Potential tertiary contacts between the conserved portion of the 3′ UTR and a region of exon 2. Positions 819 and 1756, which showed a covariation in our alignment and were the targets of site-directed mutagenesis, are indicated.