Selfish Yeast Genes Encode Both Toxin and Antidote

By spreading a poison and hoarding the remedy, wtf4 improves its chances of being inherited. 

Diana Kwon
Diana Kwon
Jun 20, 2017

Wtf4 antidote (pink) is gamete-specific and wtf4 poison (blue) acts on all sex cellsMMARÍA ANGÉLICA BRAVO NÚÑEZ AND NICOLE NUCKOLLS.

Scientists have discovered that wtf4, a gene from the yeast Schizosaccharomyces kambucha, boosts its odds of being passed down by encoding both a poison and an antidote, according to a study published today (June 20) in eLife.

In a 2014 study, Sarah Zanders, a geneticist at the Stowers Institute for Medical Research in Kansas City, and colleagues discovered that in two yeast species, S. pombe and S. kambucha, meiotic drivers—genes that boost their chances of survival by interfering with meiosis—could cause infertility.

Now, the team has uncovered one of the genes that are responsible for this effect—wtf4. This gene disrupts meiosis by generating two transcripts: one short RNA that encodes a toxic protein and one long RNA that encodes an antitoxin protein. The poison is released into the environment, killing gametes, but the antidote stays in the sex cells that retain wtf4 in their genomes, protecting them from destruction. Such toxin-antitoxin systems also exist in bacterial and archaeal cells.

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“The wtf genes make a poison that has the potential to kill everything, including themselves. That’s risky. Having this second component that’s an antidote, and keeping the antidote private, is the way they figured out how to selectively eliminate their competition,” Zanders says in a statement. “Meiotic drive systems like wtf genes could potentially be used to eradicate pest populations or to facilitate the spread of desirable traits in natural populations.”