Hybridization preceded radiation in diploid wheats

Huynh, Stella; Marcussen, Thomas; Felber, François; Parisod, Christian Gérard (2019). Hybridization preceded radiation in diploid wheats. Molecular phylogenetics and evolution, 139, p. 106554. Elsevier 10.1016/j.ympev.2019.106554

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Evolutionary relationships among the Aegilops-Triticum relatives of cultivated wheats have been difficult to resolve owing to incomplete lineage sorting and reticulate evolution. Recent studies have suggested that the wheat D-genome lineage (progenitor of Ae. tauschii) originated through homoploid hybridization between the A-genome lineage (progenitor of Triticum s.str.) and the B-genome lineage (progenitor of Ae. speltoides). This scenario of reticulation has been debated, calling for adequate phylogenetic analyses based on comprehensive sampling. To reconstruct the evolution of Aegilops-Triticum diploids, we here combined high-throughput sequencing of 38 nuclear low-copy loci of multiple accessions of all 13 species with inferences of the species phylogeny using the full-parameterized MCMC_SEQ method. Phylogenies recovered a monophyletic Aegilops-Triticum lineage that began diversifying ~6.6 Ma ago and gave rise to four sublineages, i.e. the A- (2 species), B- (1 species), D- (9 species) and T- (Ae. mutica) genome lineage. Full-parameterized phylogenies as well as patterns of tree dilation and tree compression supported a hybrid origin of the D-genome lineage from A and B ~3.0–4.0 Ma ago, and did not indicate additional hybridization events. Conflicting ABBA-BABA tests suggestive of further reticulation were shown here to result from ancestral population structure rather than hybridization. This comprehensive and dated phylogeny of wheat relatives indicates that the origin of the hybrid D-genome was followed by intense diversification into the majority of extant diploid as well as allopolyploid wild wheats.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Ecological Genomics
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Huynh, Stella and Parisod, Christian Gérard

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

1055-7903

Publisher:

Elsevier

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

27 Aug 2019 08:22

Last Modified:

24 Oct 2019 22:48

Publisher DOI:

10.1016/j.ympev.2019.106554

Uncontrolled Keywords:

Aegilops-Triticum; amplicon sequencing; hybrid speciation; multispecies coalescent network: reticulate evolution

BORIS DOI:

10.7892/boris.132587

URI:

https://boris.unibe.ch/id/eprint/132587

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