scholarly journals The role of the Andean uplift as an asymmetrical barrier to gene flow in the Neotropical leaf-cutting ant Atta cephalotes

2021 ◽  
Author(s):  
Vanessa Muñoz-Valencia ◽  
Glever Alexander Velez-Matinez ◽  
James Montoya-Lerma ◽  
Fernando Diaz
Keyword(s):  
Gene Flow ◽  
South America ◽  
Management Strategies ◽  
Atta Cephalotes ◽  
Geographical Barrier ◽  
History Of ◽  
Andean Uplift ◽  
Leaf Cutting ◽  
And Migration

Neotropical diversification by the Andean uplift is typically addressed on a large evolutionary scale (e.g. speciation), even though many species are still distributed in both sides of the mountains. The three parallel mountain ranges in the northern Andes (Colombia) impose a major geographical barrier to species' migration from South to Central America. How important these barriers are for conspecific diversification of cross-Andean species such as the leaf-cutting ants remains largely unknown. To answer this question, we studied the mtCOI gene of Atta cephalotes, the most widely distributed leaf-cutting ant species. Our hierarchical analyzes evidenced substantial genetic structure among regions and populations, suggesting a more complex biogeographical history of Andean populations than previously thought. These mountains seem to isolate Central American and Western Colombian populations from the rest of A. cephalotes in South America. Population and migration modelling are consistent with the origin of this species in South America and a major role of the Eastern cordillera as a geographical barrier to historical gene flow, restricting dispersion from north to south. These findings provide insights into the role of the Andean uplift as barrier to gene flow and, eventually, implications for monitoring and designing management strategies for leaf-cutting ants.

scholarly journals Role of the Andean uplift as an asymmetrical barrier to gene flow in the neotropical leaf‐cutting ant Atta cephalotes

Biotropica ◽  
2021 ◽  
Author(s):  
Vanessa Muñoz‐Valencia ◽  
Glever Alexander Vélez‐Matínez ◽  
James Montoya‐Lerma ◽  
Fernando Díaz
Keyword(s):  
Gene Flow ◽  
Atta Cephalotes ◽  
Andean Uplift ◽  
Leaf Cutting

Young Male with Bilateral ICA Dissection: Beyond CADISS Trial

2021 ◽  
pp. 251660852098428
Author(s):  
Vikas Bhatia ◽  
Chirag Jain ◽  
Sucharita Ray ◽  
jay Kumar
Keyword(s):  
Management Strategies ◽  
Young Male ◽  
Acute Onset ◽  
The Body ◽  
Artery Dissection ◽  
Cervical Artery Dissection ◽  
Stroke Study ◽  
History Of

Objective: To report a case of young male with stroke and bilateral internal carotid artery (ICA) dissection. Background: Cervical Artery Dissection in Stroke Study trial has provided some insight on management of patients with ICA dissection. However, there is a need to modify the management strategies as per specific clinical scenario. Design/Methods: Case report and literature review. Results: A 45-year-old male presented with 1 month old history of acute onset numbness of right half of the body with slurring of speech. Computed tomography angiography showed complete occlusion of left cervical ICA just beyond origin with presence of fusiform dilatation and spiral flap in right extracranial cervical ICA. The patient was started on antiplatelets and taken for endovascular procedure using 2-mesh-based carotid stents. Patient was discharged after 3 days on antiplatelet therapy. At 1-year follow-up, there were no fresh symptoms. Conclusion: This case emphasizes the role of successful endovascular management of carotid dissection in a young male. These clinical situations may not be fully represented in trials, and a case-based approach is required.

scholarly journals Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

A Yahgan for the killing: murder, memory and Charles Darwin

2011 ◽  
Vol 46 (3) ◽  
pp. 415-443 ◽  
Author(s):  
JOSEPH L. YANNIELLI
Keyword(s):  
South America ◽  
Charles Darwin ◽  
Historical Memory ◽  
Cross Cultural ◽  
Western Coast ◽  
Cultural Interaction ◽  
European Expansion ◽  
Multiple Contexts ◽  
History Of

AbstractIn March 1742, British naval officer John Byron witnessed a murder on the western coast of South America. Both Charles Darwin and Robert FitzRoy seized upon Byron's story a century later, and it continues to play an important role in Darwin scholarship today. This essay investigates the veracity of the murder, its appropriation by various authors, and its false association with the Yahgan people encountered during the second voyage of theBeagle(1831–1836). Darwin's use of the story is examined in multiple contexts, focusing on his relationship with the history of European expansion and cross-cultural interaction and related assumptions about slavery and race. The continuing fascination with Byron's story highlights the key role of historical memory in the development and interpretation of evolutionary theory.

Immigration, Emigration, and Migration

2017 ◽  
Keyword(s):  
Political Science ◽  
Legal Philosophy ◽  
Immigration Law ◽  
State Sovereignty ◽  
Legitimate Authority ◽  
The Us ◽  
History Of ◽  
And Migration ◽  
American Society

This volume presents chapters on the theme of borders and migration, written for the annual meetings of the American Society for Political and Legal Philosophy. It features three lead chapters and a series of responses by other scholars drawn from the fields of law, political science, and philosophy. The volume thus brings together a range of perspectives—in both disciplinary and substantive terms—on the legitimacy of borders, the development and prospects of state sovereignty, and the role of national democracies in resolving international problems. The chapters also cover a number of more specific topics including the history of immigration law in the US, the creation of the universal postal union, and the sources of legitimate authority.

scholarly journals Gene Flow between Divergent Cereal- and Grass-Specific Lineages of the Rice Blast Fungus Magnaporthe oryzae

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Pierre Gladieux ◽  
Bradford Condon ◽  
Sebastien Ravel ◽  
Darren Soanes ◽  
Joao Leodato Nunes Maciel ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Evolutionary History ◽  
Blast Disease ◽  
Whole Genome ◽  
Disease Emergence ◽  
Wheat Blast ◽  
History Of

ABSTRACT Delineating species and epidemic lineages in fungal plant pathogens is critical to our understanding of disease emergence and the structure of fungal biodiversity and also informs international regulatory decisions. Pyricularia oryzae (syn. Magnaporthe oryzae) is a multihost pathogen that infects multiple grasses and cereals, is responsible for the most damaging rice disease (rice blast), and is of growing concern due to the recent introduction of wheat blast to Bangladesh from South America. However, the genetic structure and evolutionary history of M. oryzae, including the possible existence of cryptic phylogenetic species, remain poorly defined. Here, we use whole-genome sequence information for 76 M. oryzae isolates sampled from 12 grass and cereal genera to infer the population structure of M. oryzae and to reassess the species status of wheat-infecting populations of the fungus. Species recognition based on genealogical concordance, using published data or extracting previously used loci from genome assemblies, failed to confirm a prior assignment of wheat blast isolates to a new species (Pyricularia graminis-tritici). Inference of population subdivisions revealed multiple divergent lineages within M. oryzae, each preferentially associated with one host genus, suggesting incipient speciation following host shift or host range expansion. Analyses of gene flow, taking into account the possibility of incomplete lineage sorting, revealed that genetic exchanges have contributed to the makeup of multiple lineages within M. oryzae. These findings provide greater understanding of the ecoevolutionary factors that underlie the diversification of M. oryzae and highlight the practicality of genomic data for epidemiological surveillance in this important multihost pathogen. IMPORTANCE Infection of novel hosts is a major route for disease emergence by pathogenic microorganisms. Understanding the evolutionary history of multihost pathogens is therefore important to better predict the likely spread and emergence of new diseases. Magnaporthe oryzae is a multihost fungus that causes serious cereal diseases, including the devastating rice blast disease and wheat blast, a cause of growing concern due to its recent spread from South America to Asia. Using whole-genome analysis of 76 fungal strains from different hosts, we have documented the divergence of M. oryzae into numerous lineages, each infecting a limited number of host species. Our analyses provide evidence that interlineage gene flow has contributed to the genetic makeup of multiple M. oryzae lineages within the same species. Plant health surveillance is therefore warranted to safeguard against disease emergence in regions where multiple lineages of the fungus are in contact with one another.

scholarly journals Gene flow and Andean uplift shape the diversification ofGasteracantha cancriformis(Araneae: Araneidae) in Northern South America

2018 ◽  
Vol 8 (14) ◽  
pp. 7131-7142 ◽  
Author(s):  
Fabian C. Salgado-Roa ◽  
Carolina Pardo-Diaz ◽  
Eloisa Lasso ◽  
Carlos F. Arias ◽  
Vera Nisaka Solferini ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Andean Uplift ◽  
Northern South America
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