DOI

10.30707/1734473241.700929

Document Type

Senior Thesis

Publication Date

Spring 2024

Committee Chair

Thomas Hammond

Committee Member

Pirmin Nietlisbach

Abstract

In Neurospora fungi, the ascospores formed during reproduction will most often be black and viable. Occasionally, these ascospores will end up inviable and white or yellow. The discovery of a selfish genetic element called Spore killer (Sk) in 1979 gave researchers insight into a mechanism that causes some Neurospora crosses to produce a consistent ratio of 4 black, viable ascospores and 4 inviable, white ascospores. In these 4:4 splits, the Spore killer genetic element causes the death of exactly half of the ascospores. There are now three known spore killers in Neurospora: Sk-1, Sk-2, and Sk-3. This thesis examines the role of a DNA element within Sk-3. In an Sk-3 × Sk-3-sensitive (Sk-S) cross, Sk-3 genes are transmitted to the four black, viable ascospores, and, through a poorly understood mechanism, the Sk-3 genes kill ascospores that fail to inherit these genes. The Sk-3 genes reside on Chromosome III, but the exact locations of all critical genes are unknown. Preliminary results suggest that a DNA interval called v350 may harbor a critical Sk-3 gene. For example, deletion of the v350 interval eliminates Sk-3 spore killing. Here, I explore the deletion of an additional DNA interval located within v350. Specifically, I tested the role of DNA interval v376 on Sk-3 spore killing. The research presented here should help determine why v350, and perhaps v376, are required for spore killing by Neurospora Sk-3.

Funding Source

This work was supported by the National Science Foundation (Award Number 200595, Elucidating the mechanism of meiotic drive by mRNA editing-mediated spore killing in Neurospora fungi).

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