Promotes unequal transmission of alleles from the parental zygote to progeny spores by acting as poison/antidote system where the poison and antidote proteins are produced from the same locus; the poison component is trans-acting and targets all spores within an ascus whereas the antidote component is spore-specific, leading to poisoning of all progeny that do not inherit the allele. Localizes isoform 2 to the vacuole thereby facilitating its degradation (By similarity). In addition to suppressing isoform 2, also suppresses S.pombe strain 972 wtf13 isoform 2 (PubMed:32032353). Forms toxic aggregates that disrupt spore maturation. Homomer (By similarity). Forms protein aggregates (By similarity). The two isoforms can interact with each other and with themselves (By similarity). High sequence similarity is required for their interaction (By similarity). Contained within spores expressing the isoform and localizes isoform 2 to the vacuole. Localizes in trans to all spores within an ascus. Localization to the spore vacuole is dependent on isoform 1. Belongs to the WTF family.