Figure 2

Graphs of % hybrid matings for each pairing. Bar chart showing the percentage of matings that resulted in hybrid zygotes for the five species pairs. For each pair, the light grey bar represents the result when S. cerevisiae (Sc) chose and the dark grey bar represents the result when S. paradoxus (Sp) chose. On each bar the numbers are the number of hybrid zygotes formed over the total number analysed. Dashed lines indicate the proportions of hybrids that would be expected if the chooser always mated with its own species (33.33%), had no preference (66.67%) and always mated with the other species (100%). All strains formed significantly fewer hybrids than would be expected by chance (*** = p < 0.001, ** = p < 0.01. * = p < 0.05). (For full dataset see Table 2.)