This is a new publication from Enrique Maguilla's dissertation (University Pablo de Olavide, Seville, Spain). Dr. Modesto Luceño and I supervised his dissertation about plant evolution in temperate zones using Carex sect. Glaresosae as model group. He finished his PhD in March 2017. This publication treats specifically the biogeography of Carex sect. Glareosae. We used 14 DNA regions to infer the phylogeny of Glareosae. We estimated times of diversification and diversification rates. We then performed ancestral area reconstruction analyses. The Bering Strait may have played an important role in shaping the current distribution of these species.
To disentangle the importance of the Beringian land bridges during the Pliocene and Quaternary periods in order to explain the current distribution of circumpolar plants with potential for long‐distance dispersal.
Circumpolar (Arctic and Antarctic).
We sampled all extant species in Carex section Glareosae (26 species and 2 subspecies) and analysed 14 DNA regions, including the nrDNA regions ETS and ITS, three nuclear single‐copy genes (CATP, G3PDH and GZF), and nine cpDNA regions: 5′trnK intron, atpIH, matK, ndhJ‐trnF, psbA‐trnH, rpl32‐trnL, rps16, trnC‐ycf6 and ycf6‐psbM. After testing for outlier proportions, we used Bayesian inference, maximum likelihood and a species‐tree approach to infer phylogenetic relationships between species; divergence times were estimated using Beast2. We then performed biogeographical analyses using “BioGeoBEARS” to estimate ancestral areas by means of reticulate models. Finally, lineage through time (LTT) and diversification pattern analyses were performed using Bamm.
Carex section Glareosae is a monophyletic group that diverged c. 6.56 Ma (4.54–8.51 Ma at 95% highest posterior density interval). We show that within‐area cladogenetic speciation events and anagenetic dispersal (including some vicariance events) play an important role in shaping distribution in species with potential for long‐distance dispersal. Diversification patterns show constant diversification rates over time.
The Bering Strait may have played an important role in shaping the current distribution of the species in the section, facilitating dispersal between Asia and North America during glacial periods when the Beringian land bridges were open. Nevertheless, we cannot discount long‐distance dispersal as an alternative major force shaping the species distribution in the section.
Enrique Maguilla, Marcial Escudero & Modesto Luceño. 2018. Vicariance versus dispersal across Beringian land bridges to explain circumpolar distribution: a case study in plants with high dispersal potential. Journal of Biogeography , 45, 771-783.
See the full publication here LINK.
Gene flow among incipient species can act as a creative or destructive force in the speciation process, generating variation on which natural selection can act while, potentially, undermining population divergence. The flowering plant genus Carex exhibits a rapid and relatively recent radiation with many species limits still unclear. This is the case with the Iberian Peninsula (Spain and Portugal)-endemic C. lucennoiberica, which lay unrecognized within Carex furva until its recent description as a new species. In this study, we test how these species were impacted by interspecific gene flow during speciation. We sampled the full range of distribution of C. furva (15 individuals sampled) and C. lucennoiberica (88 individuals), sequenced two cpDNA regions (atpI-atpH, psbA-trnH) and performed genomic sequencing of 45,100 SNPs using restriction site-associated DNA sequencing (RAD-seq). We utilized a set of partitioned D-statistic tests and demographic analyses to study the degree and direction of introgression. Additionally, we modelled species distributions to reconstruct changes in range distribution during glacial and interglacial periods. Plastid, nuclear and morphological data strongly support divergence between species with subsequent gene flow. Combined with species distribution modelling, these data support a scenario of allopatry leading to species divergence, followed by secondary contact and gene flow due to long-distance dispersal and/or range expansions and contractions in response to Quaternary glacial cycles. We conclude that this is a case of allopatric speciation despite historical secondary contacts, which could have temporally influenced the speciation process, contributing to the knowledge of forces that are driving or counteracting speciation.
We have been able to publish Nacho's Master Thesis. Congatulations Nacho!
It has been published in American Journal of Botany:
José I. Márquez-Corro, Marcial Escudero, Santiago Martín-Bravo, Tamara Villaverde & Modesto Luceño. 2017. Long-distance dispersal explains the bipolar disjunction in Carex macloviana (Cyperaceae). American Journal of Botany, 104, 663-673.
This a phylogeographic study of the bipolar sedge Carex macloviana.
This is the abstract of the publication:PREMISE OF THE STUDY: The sedge Carex macloviana d’Urv presents a bipolar distribution. To clarify the origin of its distribution, we consider the four main hypotheses: long-distance dispersal (either by mountain hopping or by direct dispersal), vicariance, parallel evolution, and human introduction. METHODS: Phylogenetic, phylogeographic, and divergence time estimation analyses were carried out based on two nuclear ribosomal (ETS and ITS) regions, one nuclear single copy gene (CATP), and three plastid DNA regions (rps16 and 5′trnK introns, and psbA-trnH spacer), using Bayesian inference, maximum likelihood, and statistical parsimony. Bioclimatic data were used to characterize the climatic niche of C. macloviana. KEY RESULTS: Carex macloviana constitutes a paraphyletic species, dating back to the Pleistocene (0.62 Mya, 95% highest posterior density: 0.29–1.00 Mya). This species displays strong genetic structure between hemispheres, with two different lineages in the Southern Hemisphere and limited genetic differentiation in Northern Hemisphere populations. Also, populations from the Southern Hemisphere show a narrower climatic niche with regards to the Northern Hemisphere populations. CONCLUSIONS: Carex macloviana reached its bipolar distribution by long-distance dispersal, although it was not possible to determine whether it was caused by mountain hopping or by direct dispersal. While there is some support that Carex macloviana might have colonized the Northern Hemisphere by south-to-north transhemisphere dispersal during the Pleistocene, unlike the southwards dispersal pattern inferred for other bipolar Carex L. species, we cannot entirely rule out north-to-south dispersion.
You can find the original publication here: LINK.
Two independent dispersals to the Southern Hemisphere to become the most widespread bipolar Carex species
New Publication: A clarification of the name Carex hypsipedos C.B.Clarke (Cyperaceae) and a new name for the South American Carex section Acrocystis taxon
New publications from proceedings of symposium: Phylogeny and Ecological Diversification in Carex - Botany 2015 @Edmonton - Canada
Marcial Escudero, J.I. Márquez-Corro & Andrew Hipp. 2016. The phylogenetic origins and evolutionary history of holocentric chromosomes. Systematic Botany, 41, 580-585.