Curr Biol. 2021 Jan 4;S0960-9822(20)31833-9. doi: 10.1016/j.cub.2020.12.013. Online ahead of print.

Eyal Ben-David 1, Pinelopi Pliota 2, Sonya A Widen 2, Alevtina Koreshova 2, Tzitziki Lemus-Vergara 3, Philipp Verpukhovskiy 3, Sridhar Mandali 4, Christian Braendle 5, Alejandro Burga 6, Leonid Kruglyak 7

Affiliations

1 Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel. Electronic address: eyal.bendavid@mail.huji.ac.il.
2 Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
3 Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
4 Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
5 UniversitĂ© CĂ´te d’Azur, CNRS, Inserm, IBV, Nice 06100, France.
6 Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria. Electronic address: alejandro.burga@imba.oeaw.ac.at.
7 Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA. Electronic address: lkruglyak@mednet.ucla.edu.

Abstract

Toxin-antidote elements (TAs) are selfish genetic dyads that spread in populations by selectively killing non-carriers. TAs are common in prokaryotes, but very few examples are known in animals. Here, we report the discovery of maternal-effect TAs in both C. tropicalis and C. briggsae, two distant relatives of C. elegans. In C. tropicalis, multiple TAs combine to cause a striking degree of intraspecific incompatibility: five elements reduce the fitness of >70% of the F2 hybrid progeny of two Caribbean isolates. We identified the genes underlying one of the novel TAs, slow-1/grow-1, and found that its toxin, slow-1, is homologous to nuclear hormone receptors. Remarkably, although previously known TAs act during embryonic development, maternal loading of slow-1 in oocytes specifically slows down larval development, delaying the onset of reproduction by several days. Finally, we found that balancing selection acting on linked, conflicting TAs hampers their ability to spread in populations, leading to more stable genetic incompatibilities. Our findings indicate that TAs are widespread in Caenorhabditis species and target a wide range of developmental processes and that antagonism between them may cause lasting incompatibilities in natural populations. We expect that similar phenomena exist in other animal species.

PMID: 33417886
DOI: 10.1016/j.cub.2020.12.013