The speciation continuum is the process by which genetic groups diverge until they reach reproductive isolation. It has become common in the literature to show that this process is gradual and flickering, with possibly many instances of secondary contact and introgression after divergence has started. The level of divergence might vary among genomic regions due to, among others, the different forces and roles of selection played by the shared regions.
View Article and Find Full Text PDFSpecies are seen as the fundamental unit of biotic diversity, and thus their delimitation is crucial for defining measures for diversity assessments and studying evolution. Differences between species have traditionally been associated with variation in morphology. And yet, the discovery of cryptic diversity suggests that the evolution of distinct lineages does not necessarily involve morphological differences.
View Article and Find Full Text PDFThe topographic gradients of the Tropical Andes may have triggered species divergence by different mechanisms. Topography separates species' geographical ranges and offers climatic heterogeneity, which could potentially foster local adaptation to specific climatic conditions and result in narrowly distributed endemic species. Such a pattern is found in the Andean centered palm genus .
View Article and Find Full Text PDFThe tribe Geonomateae is a widely distributed group of 103 species of Neotropical palms which contains six ecologically important understory or subcanopy genera. Although it has been the focus of many studies, our understanding of the evolutionary history of this group, and in particular of the taxonomically complex genus , is far from complete due to a lack of molecular data. Specifically, the previous Sanger sequencing-based studies used a few informative characters and partial sampling.
View Article and Find Full Text PDFGenetic diversity is key in providing the variation needed to face stochastic change. Increased habitat loss alters population size and dynamics posing serious threats to the conservation of wild species. Colombia has undergone massive deforestation over the last century, but harbors extraordinary high species diversity of genus Zamia (Cycadales); however, most of the species are under threat.
View Article and Find Full Text PDFGiven the geographical complexity of the Andes, species distributions hold interesting information regarding the history of isolation and gene flow across geographic barriers and ecological gradients. Moreover, current threats to the region's enormous plant diversity pose an additional challenge to the understanding of these patterns. We explored the geographic structure of genetic diversity within the Ceroxylon quindiuense species complex (wax palms) at a regional scale, using a model-based approach to disentangle the historical mechanisms by which these species have dispersed over a range encompassing 17° of latitude in the tropical Andes.
View Article and Find Full Text PDFWax palms are an important element of the cloud forests in the tropical Andes. Despite heavy deforestation, the density of adults seems to be similar in deforested pastures as in forests. We aimed to infer the mechanisms responsible for this apparent resilience in pastures and we tested two hypotheses to explain it: 1) adult palms survived in pastures because they were spared from logging, and 2) adults occurred in pastures through the resilience of large juvenile rosettes, which survived through subterranean meristems and later developed into adults.
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