Fig 1. Wtf poison and antidote meiotic drive.

(A) Model for how wtf meiotic drivers enhance their transmission into functional spores when heterozygous (wtf+/wtf-). wtf meiotic drivers generate both a poison and an antidote. The poison spreads throughout the ascus (sac that holds the spores). The antidote is specifically enriched within the spores that inherit the driver allele. Spores that inherit the wtf+ allele are thus overrepresented in the viable spore population. (B) Sk wtf4 uses alternate transcriptional and translational start sites to generate two transcripts. The short transcript encodes a poison from five exons and the longer transcript encodes an antidote to the poison in six exons [7]. (C) Analogous to Sk wtf4, Sp wtf13 makes two transcripts [41]. (D) Sp wtf18-2 generates one transcript with six exons. To emphasize the high amino acid identity shared by exon six of Sp wtf13 and Sp wtf18-2, those exons are depicted in blue. M’s represent the translational start sites.