title: Ancient hybridizations among the ancestral genomes of bread wheat.
abstract: The allohexaploid bread wheat genome consists of three closely related subgenomes (A, B, and D), but a clear understanding of their phylogenetic history has been lacking. We used genome assemblies of bread wheat and five diploid relatives to analyze genome-wide samples of gene trees, as well as to estimate evolutionary relatedness and divergence times. We show that the A and B genomes diverged from a common ancestor ~7 million years ago and that these genomes gave rise to the D genome through homoploid hybrid speciation 1 to 2 million years later. Our findings imply that the present-day bread wheat genome is a product of multiple rounds of hybrid speciation (homoploid and polyploid) and lay the foundation for a new framework for understanding the wheat genome as a multilevel phylogenetic mosaic.
authors.affiliation: Department of Plant Sciences, Norwegian University of Life Sciences, 1432 Ås, Norway.
authors.forename: Thomas
authors.initials: T
authors.lastname: Marcussen
authors.affiliation: Department of Plant Sciences, Norwegian University of Life Sciences, 1432 Ås, Norway. simen.sandve@nmbu.no.
authors.forename: Simen R
authors.initials: SR
authors.lastname: Sandve
authors.affiliation: Strømsveien 78 B, 0663 Oslo, Norway.
authors.forename: Lise
authors.initials: L
authors.lastname: Heier
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Spannagl
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Pfeifer
authors.affiliation: Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
authors.forename: Kjetill S
authors.initials: KS
authors.lastname: Jakobsen
authors.affiliation: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
authors.forename: Brande B H
authors.initials: BB
authors.lastname: Wulff
authors.affiliation: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Steuernagel
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Klaus F X
authors.initials: KF
authors.lastname: Mayer
authors.affiliation: Department of Plant Sciences, Norwegian University of Life Sciences, 1432 Ås, Norway.
authors.forename: Odd-Arne
authors.initials: OA
authors.lastname: Olsen
mesh_terms: D001939:Bread; D019143:Evolution, Molecular; D017343:Genes, Plant; D018745:Genome, Plant; D006824:Hybridization, Genetic; D010802:Phylogeny; D011123:Polyploidy; D014908:Triticum / Q000145:classification / Q000235:genetics*