Mitochondrial DNA and evolution of heterothallic and pseudohomothallic Neurospora species

• Published in: Mycological research Vol. 93; no. 3; pp. 257 - 272
• Main Authors: Taylor, John W., Natvig, Donald O.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1989; Elsevier
• Subjects: Biological and medical sciences; Biological evolution; chromosome fragments; chromosome mapping; DNA; Evolution; Fundamental and applied biological sciences. Psychology; genetic techniques and protocols; Genetics of eukaryotes. Biological and molecular evolution; heterothallism; Length mutations; mitochondria; Mitochondrial DNA; mutants; Neurospora; neurospora intermedia; Neurospora sitophila; neurospora tetrasperma; phylogeny; Evolution; Length mutations; Mitochondrial DNA; Neurospora; Cluster analysis; Molecular hybridization; Divergence; Genetic variability; Interspecific comparison; Outbreeding; Phylogeny; Fungi; Mating system; Molecular evolution; Restriction fragment length polymorphism; DNA; Isolate; Ascomycetes; Mutation; Thallophyta
• ISSN: 0953-7562; 1469-8102
• DOI: 10.1016/S0953-7562(89)80152-2

Length mutations are described in mitochondrial DNA (mtDNA) of 17 Neurospora isolates from two heterothallic, or outbreeding, species: N. intermedia and N. sitophila, and the pseudohomothallic and potentially outbreeding species, N. tetrasperma. This information is analyzed with mutations previously determined for 20 isolates of the heterothallic species, N. crassa. These length mutations were discovered through DNA-DNA hybridization between restriction endonuclease digested mtDNAs of natural isolates and cloned mtDNA from a laboratory strain of N. crassa. Treating these mutations as taxonomic characters, parsimony and character compatibility methods of cladistic analysis and UPGMA clustering have been used to infer evolutionary relationships among these fungi. The data indicate that isolates of N. sitophila and N. tetrasperma comprise convex and presumably monophyletic groups, but this is not true for isolates of N. intermedia or N. crassa. The greatest variability of mtDNA occurs among N. crassa and N. intermedia isolates, and the least among N. sitophila isolates. The amount of variability within a species, phenetic analysis of variability in all pairs of isolates, and mean variability in all pairs of species support the hypothesis that the 4-spored N. tetrasperma diverged from the 8-spored species first, followed by the divergence of N. sitophila. The large mtDNA variability in modern N. crassa and N. intermedia probably reflects divergences in ancestral Neurospora that predate the divergence of 4- and 8-spored species.