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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.