FIG. 1.

Deletions and other sequence features of the S. acidocaldarius pyrE gene. Horizontal open bars on the genetic map depict coding sequences of the pyrB, pyrE, and pyrF genes of S. acidocaldarius; arrows show direction of transcription. Open bars above the map show the size and location of spontaneous deletions (designated in italics). All other numbers identify nucleotide positions in the pyrE coding sequence (GenBank accession number Y12822). Positions of the first and last nucleotides removed are given above the genetic map on either side of the open bars. Regions of potential stem-loop structures, numbered in order of decreasing thermodynamic stability, are indicated above the map. The first and last nucleotides of these regions (in roman numerals) are as follows: I, 200 to 217; II, 133 to 153; III, 67 to 88; IV, 528 to 541; V, 481 to 508, VI, 340 to 350. Regions which have been duplicated by various spontaneous mutations are represented by the trapezoidal symbols below the genetic map. Sites of frequent mutation are shown as partial sequences in parentheses below the map; numbers indicate the position of the first nucleotide in each region. More-detailed information on the gene sequence and mutations are provided in reference 15.