Figure 3. Test of allelism at seed sterility locus sss1.2.

A) Chromosomal location (shaded) of SP and SH introgressions represented in IL_PP and IL_HH lines, respectively, used in cross-species tests. Marker IDs (solgenomics.org) are shown to the right (SP) or left (SH) of chromosome 7. B) Seed fertility (number of viable seed per fruit) in 4 genotypes (SL = S. lycopersicum; IL_HH = introgression line with homozygous SH alleles; IL_PP = introgression line with homozygous SP alleles; IL_HP = heterointrogression line (from IL_HH maternal parent)). C) Inferred placement of two mutational changes (sss1.2.1, sss1.2.2) underlying sss1.2. Note that introgression regions corresponding to sss1.2 in the SP versus SH lines are incompletely overlapping (Fig. 2A), with an additional distal heterospecific region represented in line IL_PP but not in IL_HH; therefore sss1.2.2 could be located within the introgressed region unique to IL_PP. Regardless, because no IL_HH line exhibited reduced seed fecundity at this genomic location in the original SH×SL mapping experiment [7], our results are consistent with the inference that sss1.2.2 is SP-specific.