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Neurospora Spore killer-3 (Sk-3) is a selfish genetic element that kills spores to achieve gene drive. Here, we describe the isolation and mapping of rfk-2UV, a mutation that disrupts spore killing. The rfk-2UV mutation is located 15.6 cM from mus-52 on Chromosome III. The significance of this discovery with respect to Sk-3 evolution is discussed
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An introgressed gene causes meiotic drive in Neurospora sitophila
Meiotic drive elements cause their own preferential transmission following meiosis. In fungi, this phenomenon takes the shape of spore killing, and in the filamentous ascomycete Neurospora sitophila , the Sk-1 spore killer element is found in many natural populations. In this study, we identify the gene responsible for spore killing in Sk-1 by generating both long- and short-read genomic data and by using these data to perform a genome-wide association test. We name this gene Spk-1 . Through molecular dissection, we show that a single 405-nt-long open reading frame generates a product that both acts as a poison capable of killing sibling spores and as an antidote that rescues spores that produce it. By phylogenetic analysis, we demonstrate that the gene has likely been introgressed from the closely related species Neurospora hispaniola , and we identify three subclades of N. sitophila , one where Sk-1 is fixed, another where Sk-1 is absent, and a third where both killer and sensitive strain are found. Finally, we show that spore killing can be suppressed through an RNA interference-based genome defense pathway known as meiotic silencing by unpaired DNA. Spk-1 is not related to other known meiotic drive genes, and similar sequences are only found within Neurospora . These results shed light on the diversity of genes capable of causing meiotic drive, their origin and evolution, and their interaction with the host genome.
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- Award ID(s):
- 2005295
- PAR ID:
- 10282324
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 118
- Issue:
- 17
- ISSN:
- 0027-8424
- Page Range / eLocation ID:
- e2026605118
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1073/pnas.2026605118
