Promotes unequal transmission of alleles from the parental zygote to progeny spores by acting as poison/antidote system, leading to poisoning of progeny that do not inherit the allele (PubMed:24830502, PubMed:31347500). Can suppress meiotic drive by the P.anserina SPOK2, SPOK3 and SPOK4 proteins (PubMed:24830502, PubMed:31347500). Present in both spores and vegetative cells. Sensitises spores to SPOK1 encoded poison.