Inga hybridisation resequencing data
The Amazon rain forest holds the highest diversity of plant species on Earth, but the mechanisms which gave rise to this superlative diversity remain enigmatic. Recent studies point to a large contribution of rapid and recent diversification (i.e., formation of new species) in species-rich tree genera. Inga, the focus of this project, is an exemplar for these recent radiations, having evolved at least 300 species in the last 6 million years in the Amazon and other Latin American rain forests. Moreover, in Amazonia hundreds of tree species can coexist in a single hectare (up to 300), and this extremely high local diversity is largely composed of relatively few species-rich genera such as Inga. The high overall and local diversity of Amazonian forests suggests parallels with other species-rich systems where evolutionary radiation - the rapid rise of many species from one progenitor population – produced many new lineages. Here, we aim to develop Inga as a model for plant species radiation in Amazonia.  In particular, we investigate the role of hybridization, the interbreeding between groups of species, as recent work shows it is a major cause of evolutionary radiations. Hybridization's effect on evolutionary radiation has not yet been studied within tropical trees, despite being widely acknowledged as a powerful creative force in plant evolution. Hybridization generates morphological and genetic novelty, impacting the rate of speciation in many groups and is evident in all major adaptive radiation events for which multiple sequenced genomes exist. In plants, one mechanism of speciation, polyploidy or the doubling of genome size, which is often linked with hybridisation, is known to be particularly important. While the prevailing view has been that hybridization between tropical tree species is exceptionally rare, this view is challenged by recent DNA sequence data. In Inga, hybridization has been recently demonstrated to occur, despite prior reports of species intersterility, and a few chromosome counts have demonstrated that unrelated species are polyploid.    Here, using whole-genome resequencing for the first time in Amazonian trees to test the significance of hybridization and polyploidy in Inga diversification.
The Amazon rain forest holds the highest diversity of plant species on Earth, but the mechanisms which gave rise to this superlative diversity remain enigmatic. Recent studies point to a large contribution of rapid and recent diversification (i.e., formation of new species) in species-rich tree genera. Inga, the focus of this project, is an exemplar for these recent radiations, having evolved at least 300 species in the last 6 million years in the Amazon and other Latin American rain forests. Moreover, in Amazonia hundreds of tree species can coexist in a single hectare (up to 300), and this extremely high local diversity is largely composed of relatively few species-rich genera such as Inga. The high overall and local diversity of Amazonian forests suggests parallels with other species-rich systems where evolutionary radiation - the rapid rise of many species from one progenitor population – produced many new lineages. Here, we aim to develop Inga as a model for plant species radiation in Amazonia.  In particular, we investigate the role of hybridization, the interbreeding between groups of species, as recent work shows it is a major cause of evolutionary radiations. Hybridization's effect on evolutionary radiation has not yet been studied within tropical trees, despite being widely acknowledged as a powerful creative force in plant evolution. Hybridization generates morphological and genetic novelty, impacting the rate of speciation in many groups and is evident in all major adaptive radiation events for which multiple sequenced genomes exist. In plants, one mechanism of speciation, polyploidy or the doubling of genome size, which is often linked with hybridisation, is known to be particularly important. While the prevailing view has been that hybridization between tropical tree species is exceptionally rare, this view is challenged by recent DNA sequence data. In Inga, hybridization has been recently demonstrated to occur, despite prior reports of species intersterility, and a few chromosome counts have demonstrated that unrelated species are polyploid.    Here, using whole-genome resequencing for the first time in Amazonian trees to test the significance of hybridization and polyploidy in Inga diversification.
University of Exeter