Identification of , a Meiotic Driver Undergoing RNA Editing in .

is a meiotic drive element that was discovered in wild populations of fungi over 40 years ago. While early studies quickly determined that transmits itself through sexual reproduction in a biased manner via spore killing, the genetic factors responsible for this phenomenon have remained mostly unknown. Here, we identify and characterize , a gene required for -based spore killing. The gene contains four exons, three introns, and two stop codons, the first of which undergoes RNA editing to a tryptophan codon during sexual development. Translation of an unedited transcript in vegetative tissue is expected to produce a 102-amino acid protein, whereas translation of an edited transcript in sexual tissue is expected to produce a protein with 130 amino acids. These findings indicate that unedited and edited transcripts exist and that these transcripts could have different roles with respect to the mechanism of meiotic drive by spore killing. Regardless of RNA editing, spore killing only succeeds if transcripts avoid silencing caused by a genome defense process called meiotic silencing by unpaired DNA (MSUD). We show that 's MSUD avoidance mechanism is linked to the genomic landscape surrounding the gene, which is located near the border on the right arm of chromosome III. In addition to demonstrating that the location of is critical to spore-killing success, our results add to accumulating evidence that MSUD helps protect genomes from complex meiotic drive elements.