Figure 1.
Sk-2INS1 harbors a genetic element required for spore killing. (A) The diagram illustrates phenotypic differences between spore killing and normal ascus development. Asci that have undergone spore killing contain four black and four white ascospores. Viable ascospores may appear tan, brown, or black, depending on their level of maturity. (B) Annotation of the rfk-1 region as described by Harvey et al. (2014). Genes and pseudogenes are depicted as black rectangles. Gene names (e.g., 6197) are listed above the rectangles. Pseudogene names are appended with an asterisk. Labels v3, v4, and v5 mark DNA intervals of the rfk-1 region, which were deleted and replaced with an hph selectable marker. (C–E) The images depict asci from crosses between SkS and Sk-2 strains lacking different intervals of the rfk-1 region. The predominant phenotype of the asci produced by each cross is listed above its image. Crosses are as follows: (C) F2-23 × ISU-3023, (D) F2-23 × ISU-3017, and (E) F2-23 × ISU-3029. B, black; W, white.