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Abstract Detail

Hybrids and Hybridization

Manos, Paul [1], Hipp, Andrew [2], McVay, John [1].

A phylogeny of the American white oaks reveals widespread divergent evolution and the genomic legacy of introgressive hybridization.

Oaks (Quercus L.) have long been suspected to hybridize in nature. Genetic exchange between morphologically-defined oak species has challenged the biological species concept, but the genomic consequences of introgressive hybridization have never been demonstrated. Here we show that phylogenomic analyses generally support morphologically defined species and reveal novel clades of species alliances of white oaks; however, historical hybridization across species from divergent clades is both detectable and the cause of misinterpreting biogeographic history. Total evidence phylogenetic estimation from RADseq data for 153 individuals representing 80 species supports two Holarctic disjunctions, one between the American white oaks and Eurasian “Roburoids”, the other linking two relictual species of highly localized distribution. We systematically analyzed the data using subsamples along multiple parameter axes and found support for a more recent derivation of the Roburoids from within the American white oaks, a scenario consistent with fossil data. An unexpected result is that ancient introgression between the Roburoids and the single species representing the relictual Eurasian lineage bias concatenated phylogenetic estimates. We also identify cases of historical hybridization between species and across oak subclades, including the origination of a geographically isolated species with genomic footprints of introgression that derive from three distinct lineages. These results demonstrate that a combination of divergent and reticulate processes have promoted the diversification and spread of these ecologically and economically important taxa in the northern hemisphere.

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1 - Duke University, Biology, Box 90338, Durham, NC, 27708, USA
2 - The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL, 60532-1293, USA


Presentation Type: Oral Paper
Session: 50, Hybrids and Hybridization
Location: 102/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 5:15 PM
Number: 50007
Abstract ID:838
Candidate for Awards:Margaret Menzel Award

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