Introgression across evolutionary scales suggests reticulation contributes to Amazonian tree diversity
Molecular Ecology, vol. 29, pp. 4170–4185
Abstract
Hybridization has the potential to generate or homogenize biodiversity and is a particularly common phenomenon in plants, with an estimated 25% of plant species undergoing interspecific gene flow. However, hybridization in Amazonia's megadiverse tree flora was assumed to be extremely rare despite extensive sympatry between closely related species, and its role in diversification remains enigmatic because it has not yet been examined empirically. Using members of a dominant Amazonian tree family (Brownea, Fabaceae) as a model to address this knowledge gap, our study recovered extensive evidence of hybridization among multiple lineages across phylogenetic scales. More specifically, using targeted sequence capture our results uncovered several historical introgression events between Brownea lineages and indicated that gene tree incongruence in Brownea is best explained by reticulation, rather than solely by incomplete lineage sorting. Furthermore, investigation of recent hybridization using ~19,000 ddRAD loci recovered a high degree of shared variation between two Brownea species that co-occur in the Ecuadorian Amazon. Our analyses also showed that these sympatric lineages exhibit homogeneous rates of introgression among loci relative to the genome-wide average, implying a lack of selection against hybrid genotypes and persistent hybridization. Our results demonstrate that gene flow between multiple Amazonian tree species has occurred across temporal scales, and contrasts with the prevailing view of hybridization's rarity in Amazonia. Overall, our results provide novel evidence that reticulate evolution influenced diversification in part of the Amazonian tree flora, which is the most diverse on Earth.
Authors 10
-
Rowan Schley corresponding
Royal Botanic Gardens, Kew · Imperial College London
Affiliation as printed
Department of Life Sciences Imperial College London Ascot Berkshire London UK
Royal Botanic Gardens, Kew Richmond UK
Department of Life Sciences, Imperial College London, Ascot, Berkshire, London, UK
Royal Botanic Gardens, Kew, Richmond, UK
-
Royal Botanic Garden Edinburgh · University of Exeter
Affiliation as printed
Geography University of Exeter Exeter UK
Royal Botanic Garden Edinburgh Edinburgh UK
Geography, University of Exeter, Exeter, UK
Royal Botanic Garden Edinburgh, Edinburgh, UK
-
Affiliation as printed
Royal Botanic Gardens, Kew Richmond UK
Royal Botanic Gardens, Kew, Richmond, UK
-
Diversité, adaptation et développement des plantes · Institut de Recherche pour le Développement
Affiliation as printed
Institut de Recherche pour le Développement (IRD) UMR‐DIADE Montpellier France
-
Affiliation as printed
Departamento de Botánica Ecología y Fisiología Vegetal Facultad de Ciencias Universidad de Córdoba Córdoba Spain
-
Royal Botanic Gardens, Kew · Ghent University
Affiliation as printed
Royal Botanic Gardens, Kew Richmond UK
Systematic and Evolutionary Botany Lab Department of Biology Ghent University, K.L Gent Belgium
Royal Botanic Gardens, Kew, Richmond, UK
Systematic and Evolutionary Botany Lab, Department of Biology, Ghent University, K.L, Gent, Belgium
-
Izai A. B. Sabino Kikuchi Aachen
Leiden University · Royal Botanic Gardens, Kew
Affiliation as printed
Royal Botanic Gardens, Kew Richmond UK
Universiteit Leiden Hortus botanicus Leiden Leiden The Netherlands
Royal Botanic Gardens, Kew, Richmond, UK
Universiteit Leiden, Hortus botanicus Leiden, Leiden, The Netherlands
-
University of Oxford · Imperial College London
Affiliation as printed
Department of Life Sciences Imperial College London Ascot Berkshire London UK
Department of Zoology University of Oxford Oxford UK
Department of Life Sciences, Imperial College London, Ascot, Berkshire, London, UK
Department of Zoology, University of Oxford, Oxford, UK
-
Affiliation as printed
Royal Botanic Gardens, Kew Richmond UK
Royal Botanic Gardens, Kew, Richmond, UK
-
Affiliation as printed
Royal Botanic Gardens, Kew Richmond UK
Royal Botanic Gardens, Kew, Richmond, UK
Cited by 41 stored of 41
No patents citing this paper on Lens.org (checked 2026-10-11).