Article

Diversification in the Andes: Age and origins of South American Heliotropium lineages (Heliotropiaceae, Boraginales)

Freie Universität Berlin, Institut für Biologie - Botanik, Altensteinstraße 6, D-14195 Berlin, Germany.
Molecular Phylogenetics and Evolution (Impact Factor: 4.02). 06/2011; 61(1):90-102. DOI: 10.1016/j.ympev.2011.06.001
Source: PubMed

ABSTRACT The uplift of the Andes was a major factor for plant diversification in South America and had significant effects on the climatic patterns at the continental scale. It was crucial for the formation of the arid environments in south-eastern and western South America. However, both the timing of the major stages of the Andean uplift and the onset of aridity in western South America remain controversial. In this paper we examine the hypothesis that the Andean South American groups of Heliotropium originated and diversified in response to Andean orogeny during the late Miocene and a the subsequent development of aridity. To this end, we estimate divergence times and likely biogeographical origins of the major clades in the phylogeny of Heliotropium, using both Bayesian and likelihood methods. Divergence times of all Andean clades in Heliotropium are estimated to be of late Miocene or Pliocene ages. At least three independent Andean diversification events can be recognized within Heliotropium. Timing of the diversification in the Andean lineages Heliotropium sects.Heliothamnus, Cochranea, Heliotrophytum, Hypsogenia, Plagiomeris, Platygyne clearly correspond to a rapid, late Miocene uplift of the Andes and a Pliocene development of arid environments in South America.

Download full-text

Full-text

Available from: Maximilian Weigend, Aug 29, 2015
3 Followers
 · 
218 Views
    • "Another possibility for lower divergence among the South American taxa is that radiation and speciation has, in general, been more recent in the Andes than in Mexico. The low diver­ gence among members of the Andean clade fits a pattern seen in several other groups in the Andes where relatively recent uplift has provided environments for colonization (Hughes & Eastwood, 2006; Drummond, 2008; Luebert & al., 2011). Even the most divergent species in South America are only half as divergent as the most divergent Mexican taxa. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Coreopsis (Asteraceae) sect. Pseudoagarista is the largest section in the genus. It is disjunct between the high mountains of Mexico and high elevations in the Andes. Most species in the section are similar in floral and fruit characters, and are distinguished primarily by leaf characters. Despite the morphological similarity among all species, the monophyly of the section has been called into question by molecular data. Prior studies of tribe Coreopsideae have been equivocal with, cpDNA markers indicating monophyly but nrDNA ITS sequences have not resolved the section as monophyletic. Expanded cpDNA and nrDNA ITS datasets, and statistical (i.e., AU) tests of the ITS and cpDNA topologies provide support that sect. Pseudoagarista is not monophyletic. Both data partitions strongly support the Mexican and South American subclades as monophyletic. The low cpDNA sequence variation within each subclade provides no resolution, and thus patterns of evolution within each were examined using a phylogenetic framework estimated from ITS data. Sequences from ITS fail to provide high resolution of relationships among South American species, a likely result of a recent, rapid radiation, as is known in other Andean lineages. Divergence among species is generally higher in the Mexican species, resulting in better resolution of phylogenetic relationships compared to South American species. Three ploidy levels (diploid, tetraploid, hexaploid) are known in species from South America, and diploids and tetraploids have been documented in Mexico. Multiple origins of polyploidy are indicated for both geographic areas.
    Taxon 10/2014; 63(5). DOI:10.12705/635.31 · 3.05 Impact Factor
  • Source
    • "Cochranea underwent an adaptive radiation toward the early Pliocene in response to the aridification of the Atacama Desert (Luebert and Wen 2008; Luebert et al. 2011a,b2011b). However, sister relationships are largely unresolved, and little is known about the ecological and genetic forces as well as the spatial and temporal dynamics implied in its diversification. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The genetic structure of populations of closely related, sympatric species may hold the signature of the geographical mode of the speciation process. In fully allopatric speciation, it is expected that genetic differentiation between species is homogeneously distributed across the genome. In nonallopatric speciation, the genomes may remain undifferentiated to a large extent. In this article, we analyzed the genetic structure of five sympatric species from the plant genus Heliotropium in the Atacama Desert. We used amplified fragment length polymorphisms (AFLPs) to characterize the genetic structure of these species and evaluate their genetic differentiation as well as the number of loci subject to positive selection using divergence outlier analysis (DOA). The five species form distinguishable groups in the genetic space, with zones of overlap, indicating that they are possibly not completely isolated. Among-species differentiation accounts for 35% of the total genetic differentiation (F ST = 0.35), and F ST between species pairs is positively correlated with phylogenetic distance. DOA suggests that few loci are subject to positive selection, which is in line with a scenario of nonallopatric speciation. These results support the idea that sympatric species of Heliotropium sect. Cochranea are under an ongoing speciation process, characterized by a fluctuation of population ranges in response to pulses of arid and humid periods during Quaternary times.
    Ecology and Evolution 02/2014; 4(3):266-75. DOI:10.1002/ece3.929 · 1.66 Impact Factor
  • Source
    • "A high diversity of Stachys species is also found in South America (SA), particularly in the Andean region. The powerful effect of the Andean orogeny has led to rapid diversification and radiations in the Andean flora (Luebert et al., 2011), and the Andean mountain ranges with their high altitude flora are the seat of a variety of species (Marx et al., 2010; Tank and Olmstead, 2009; Turchetto-Zolet et al., 2013). The rapid radiation in this region is comparable in many instances to that observed in oceanic islands (Drummond et al., 2012; Hughes and Eastwood, 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Due to its unique geological history and isolated location, the Hawaiian Archipelago provides an ideal setting for studies on biogeography, phylogeny and population biology. Species richness in these islands has been attributed to unique colonization events. The Hawaiian mints comprising of three endemic genera represent one of the largest radiations in the island. Previous studies have shown the Hawaiian mints to be nested within the dry-fruited Stachys, probably resulting from one or more hybridization events. Stachydeae, the largest tribe in the subfamily Lamioideae (Lamiaceae), is a taxonomically complex and widespread lineage exhibiting remarkable chromosomal diversity. In this paper we attempted at untangling the relationships between the New World and Hawaiian mint taxa, as well as investigate the origin and diversification of the mints in the New World. There seem to have been at least two independent migration events of Stachys to the New World during the Middle to Late Miocene and towards the beginning of the Pliocene, respectively. Results indicate incongruence between the rDNA and cpDNA phylogenies suggesting a reticulate, New World origin for the Hawaiian mints, although dispersal to Hawaii appears to have happened only once during the Pliocene. South American Stachys diversified from their Mesoamerican relatives around Late Pliocene and may also have arisen from similar reticulate events indicated by their intercalating position among the Mesoamerican Stachys species. Further insights into the phylogenetic relationships between the New World mints may be gathered through the study of low copy nuclear loci.
    Molecular Phylogenetics and Evolution 06/2013; 69(1). DOI:10.1016/j.ympev.2013.05.023 · 4.02 Impact Factor
Show more