Rapid Radiation in Aframomum (Zingiberaceae):evidence From Nuclear Ribosomal Dna Internal Transcribed Spacer (Its) Sequences

A phylogenetic analysis of the tribe Zingibereae (Zingiberaceae) was performed using nuclear ribosomal DNA (ITS1, 5.8S and ITS2) and chloroplast DNA (trnL (UAA) 5p exon to trnF (GAA)). The tribe is monophyletic with two major clades, the Curcuma clade and the Hedychium clade. Paracautleya, sampled for the first time, comes out as predicted while Caulokaempferia comes out in a different position from that found in another recent study. The genera Boesenbergia and Curcuma are apparently not monophyletic.

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“…comm. ) where ITS variation is exceptionally low: 0-2.74% (Harris et al, 2000). The mechanism can be further explained by ecological factors.…”

Section: Evolution Of Its and Trnl-fmentioning

confidence: 92%

THE PHYLOGENY OF TRIBE ZINGIBEREAE (ZINGIBERACEAE) BASED ON ITS (nrDNA) AND trnL–F (cpDNA) SEQUENCES

2004

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“…Mayr and O'Hara 1986;Rietkerk et al 1996;Robbrecht 1996;Sosef 1996;Leal 2004). Several recent phylogenetic studies have also suggested that, in tropical Africa, refuges could explain an important part of the current distribution of certain birds (Bowie et al 2006), mammals (Querouil et al 2003;Anthony et al 2007) and vascular plants (Harris et al 2000;Plana et al 2004). The refuge theory has been widely embraced in the African context but remains controversial in South America, where several alternative or complementary assumptions have been proposed to explain the processes that have generated the remarkable diversity of tropical forests there (Haffer 1997;Moritz et al 2000;Hill and Hill 2001).…”

Section: Introductionmentioning

confidence: 99%

Do plant families with contrasting functional traits show similar patterns of endemism? A case study with Central African Orchidaceae and Rubiaceae

et al. 2011

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International audienceThe influence of functional traits on floristic patterns remains poorly understood in tropical rain forests. This contribution explores whether patterns of endemism of plant species are influenced by their life form and mode of dispersal. We used a comprehensive dataset of 3650 georeferenced plant specimens collected in Cameroon belonging to 115 taxa of Orchidaceae and 207 Rubiaceae endemic to Atlantic Central Africa. Species diversity of each family was compared using raw species richness (SR) and an index of species diversity (S k ) using subsampling procedure to correct for sampling bias. Measures were compared at three scales (square grids of one half-degree and one-degree per side and ecoregions) and according to elevation and continentality gradients. Species similarity between grid cells was measured using the sample-size corrected NNESS index. For both families, SR and S k decreased along the continentality gradient. In forest habitats below 1500 m altitude, both Orchidaceae and Rubiaceae show similar endemism patterns, but they differ in intensity. At higher altitudes, S k is higher for orchids due to the presence of endemic terrestrial taxa in grasslands, where the endemic Rubiaceae flora is rather poor. Substantial endemism observed at the ecoregion level and turnover analysis supported the role of the Sanaga River as a phytogeographical boundary. Similar endemism patterns were observed in lowland forests for Orchidaceae and Rubiaceae, even though Orchidaceae are assumed to have better long distance dispersal capabilities. The dispersal ability of Orchidaceae could be limited by the need of specific mycorhizal fungi for seed germination or host specificity for epiphytic orchid

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“…Rapidly mutating regions are soon over-saturated if the radiation occurred deep in time, and like slowly mutating regions are unable to capture a radiation that is very recent (Harris et al, 2000;Bateman, 2001;Richardson et al, 2001ft). In other words, the absence of a morphological clock gives the phenotype a clear advantage over the genotype in resolving bonafide radiations, by weight of phylogenetic evidence.…”

Section: Dating and Interpreting Major Diversification Events: Roles mentioning

confidence: 99%

Genesis of phenotypic and genotypic diversity in land plants: The present as the key to the past

Bateman

DiMichele

2003

Systematics and Biodiversity

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The evolutionary history of vascular plants is reviewed by extrapolation back through time from a wide range of data recently derived from the present flora, using as the central theme evolutionary inferences gained from phylogenies reconstructed as cladograms. Any region of the genome can be used to infer relationships, but only a combination of knowledge of morphology and the developmental genes that underpin morphology can allow evolutionary interpretation of macroevolutionary transitions; this in turn is necessary to identify bona fide evolutionary radiations and any putative causal key innovations. Such studies require clades to be delimited not by the inclusion of particular extant 'crown' species but rather by specific apomorphies, thereby giving important phylogenetic roles to extinct as well as extant species. Dating phylogenetic divergences via molecular clocks remains seriously inaccurate, and ultimately relies primarily on fossil benchmarks. First principles suggest that evolution of most regions of the genome is fundamentally gradual, whereas evolution of regions especially prone to strong selection pressure, and of the many facets of the phenotype, is punctuational, being characterized through time dominantly by stasis. Sequence data have proved valuable for inferring monophyletic groups, but within the now widely accepted context of monophyly the taxonomic hierarchy should primarily reflect degrees of morphological rather than molecular divergence. Incongruence among contrasting data sets is best explained by understanding the biological constraints operating on each type of phylogenetic information. The conventional 'uniformitarian' view of evolution has only limited applicability as one traces the history of land plants through time. Diversity increased in stepwise fashion, reflecting either attainments of complexity and/or fitness thresholds by the lineage (intrinsic) or the availability of unusually permissive environments, often following major perturbations (extrinsic). The Quaternary period demonstrates especially well the resilience, and ease of migration, of the Earth's vegetation. A higher frequency of generation of novel phenotypes in the deep past is possible, but a far higher frequency of their establishment is certain; together, these factors generate an evolutionary pattern of nested radiations that is fractal, as saturation of the resource space rendered the environment decreasingly permissive through time.In the immediate future, evolutionary-developmental genetics will have increasing value for testing homology, interpreting homoplasy and elucidating evolutionary constraints, and will become easierto pursue as whole-genome sequences of additional 'model' species further invigorate comparative genomics. Complexity of gene regulation, both by other genes and by the cellular and extra-cellular environment, appears a particularly fruitful area for further research. Nonetheless, environmental filtering of evolutionary novelties (whether instantaneously isolated mutant 'prospec...

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Rapid Radiation in Aframomum (Zingiberaceae):evidence From Nuclear Ribosomal Dna Internal Transcribed Spacer (Its) Sequences

Cited by 43 publications

References 3 publications

THE PHYLOGENY OF TRIBE ZINGIBEREAE (ZINGIBERACEAE) BASED ON ITS (nrDNA) AND trnL–F (cpDNA) SEQUENCES

THE PHYLOGENY OF TRIBE ZINGIBEREAE (ZINGIBERACEAE) BASED ON ITS (nrDNA) AND trnL–F (cpDNA) SEQUENCES

Do plant families with contrasting functional traits show similar patterns of endemism? A case study with Central African Orchidaceae and Rubiaceae

Genesis of phenotypic and genotypic diversity in land plants: The present as the key to the past

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