Cytological phenotypes of wild-type and rec12 mutant asci. (A-B) DIC (left) and DAPI fluorescence (right) images of asci. In addition to aberrant ascus morphology, variable spore number, and unequal DNA content, some rec12 mutant asci show evidence of trailing DNA and chromatin bridges (arrows). The data were from crosses of strains: WSP0602 × WSP0603; WSP0332 × WSP0335 or WSP0079 × WSP1799; WSP1813 × WSP1819; and WSP1556 × WSP1559. (C) Summary of cytological phenotypes in wild-type, rec12-117, rec12-D15, and rec12-Y98F. Randomly selected asci were classified based upon DNA content and distribution (black dots), spore coat formation (circles), and ascus morphology (peripheral oval) using data such as in Panel B. Between 187 and 300 asci were scored for each group. Photomicrographs corresponding to classes "f," "l," and "j" are shown in Panel B.