Neurospora

An Ascomycete fungus, haploid and grows as a mycelium. There are two mating types, and fusion of nuclei of two opposite types leads to meiosis followed by mitosis. The resulting eight nuclei generate eight ascospores, arranged linearly in an ordered fashion in a pod-like ascus so that the various products of meiotic division can be identified and isolated. Because of this, Neurospora crassa is one of the classic organisms for genetic research; studies on biochemical mutants led Beadle & Tatum to propose the seminal "one gene-one enzyme" hypothesis.