You are interested in studying the evolution of Rnase-based gametophytec self-incompatibility. You go into a population and identify 4 5-alleles present. These alleles are designated $1, S2, $3, and S4, and they occur in the sporophyte only as heterozygous at equal frequency, in each of the 6 possible combinations: S152 S153 S154 S253 S254 S3S4 Assuming random dispersal of pollen, what fraction of S1 pollen grains that land on stigmas will be able to fertilize ovules in this population? Why