Phylogeny of Renealmia - Diversification rates in Renealmia

    Project: Research project

    Project Details

    Description

    The known high species richness of the tropical forests is not uniform in its different regions; Africa is poor in species compared to Southeast Asia and the neotropical region. One of the hypotheses of the differences between the richness in the Neotropics and Africa points to the importance of recent speciation in the Neotropics. This is considered particularly in Andes-centered taxa that probably diversified in response to the opportunities for speciation offered by the final uplift of the tropical Andes (during the last 25 million years [Ma] to the present, with higher rates in the past 10 Ma to the present). The aim of this thesis is to test this hypothesis in the genus Renealmia Lf (Zingiberaceae), an Andean-centered lineage (c. 64 Neotropical spp.) also found in Africa (c. 17 spp.). A taxonomic count of Colombian species is presented (c. 32; the country with the most species) and three new species were discovered for science and are described in an updated review. I designed a new approach to obtain nuclear phylogenetic markers to estimate phylogenies at the species level using transcriptomes for recent diversification that could be applied to samples of herbarium specimens. I generated de novo transcripts for two species of Renealmia and a relative of the Alpinioideae subfamily that were combined with available data from repositories to target low copy numbers and potentially short intron ortho genes. I obtained sequence data for eight introns (ranging from 219 to 924 bp) and rRNA marker (ITS1 and ITS2) for 40 species and at least one marker for 64 species, comprising a total of 137 accessions, of which 67.9% (93) were sampled from herbarium specimens. Genetic trees and species were estimated for the genus. I found that most of the subgroups based on morphological characters are supported by molecular data, but a possible combination of incomplete lineage classification (related to recent radiation or large population sizes) and/or introgression through hybridization makes it difficult to solve the relationships between these subgroups. Finally, I estimated and compared the diversification rates of Neotropical and African lineages using dated phylogenies based on the estimated trees. I used available and customized methods that take into account incomplete taxon sampling, uncertainty in phylogenetic relationships, and stochasticity inherent to diversification processes.
    StatusFinished
    Effective start/end date7/1/1612/1/18

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