A global multilocus analysis of the model fungus Neurospora reveals a single recent origin of a novel genetic system.
The large diversity of mating systems observed in the fungal kingdom underlines the importance of mating system change in fungal evolution. The selfing species Neurospora tetrasperma has evolved a novel method of achieving self-fertility by a mating system referred to as pseudohomothallism. However, little is known about the origin of N. tetrasperma and its relationship to the self-sterile, heterothallic, Neurospora species. In this study, we used a combination of phylogenetic and population genetic analyses to reconstruct the evolutionary history of N. tetrasperma and its heterothallic relatives. We sequenced 9 unlinked nuclear loci from 106 strains of N. tetrasperma sampled from across the globe, and a sample of 28 heterothallic strains of Neurospora. Our analyses provide strong support for monophyly of N. tetrasperma, but reject the monophyly of N. crassa. We estimate that N. tetrasperma is of a recent origin and that it diverged from the heterothallic species ∼1 million years ago. We also extend previous findings on the diversification within the N. tetrasperma clade, with 10 lineages identified. Taken together, these findings indicate that N. tetrasperma is younger than has been previously reported and that a rapid diversification of lineages has occurred within the N. tetrasperma clade.
Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden. Electronic address: padraic.corcoran@ebc.uu.se.
Pádraic
P
Corcoran
Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
Jeremy R
JR
Dettman
Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden.
Yu
Y
Sun
Departamento de Genética, Universidad de Sevilla, Sevilla, Spain.
Eva M
EM
Luque
Departamento de Genética, Universidad de Sevilla, Sevilla, Spain.
Luis M
LM
Corrochano
Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA.
John W
JW
Taylor
Department of Plant Ecology and Evolution, Uppsala University, Uppsala, Sweden.
Martin
M
Lascoux
Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden.
Hanna
H
Johannesson
D014644:Genetic Variation; D009491:Neurospora / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA
Divergence time; Fungi; Mating systems; Neurospora; Phylogenetics; Population structure