scholarly journals Understanding the Adaptive Evolutionary Histories of South American Ancient and Present-Day Populations via Genomics

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 360
Author(s):  
John Lindo ◽  
Michael DeGiorgio

The South American continent is remarkably diverse in its ecological zones, spanning the Amazon rainforest, the high-altitude Andes, and Tierra del Fuego. Yet the original human populations of the continent successfully inhabited all these zones, well before the buffering effects of modern technology. Therefore, it is likely that the various cultures were successful, in part, due to positive natural selection that allowed them to successfully establish populations for thousands of years. Detecting positive selection in these populations is still in its infancy, as the ongoing effects of European contact have decimated many of these populations and introduced gene flow from outside of the continent. In this review, we explore hypotheses of possible human biological adaptation, methods to identify positive selection, the utilization of ancient DNA, and the integration of modern genomes through the identification of genomic tracts that reflect the ancestry of the first populations of the Americas.

The analysis of integration of the legal systems of states in the American region is held. In the Southern subregion, a combination of integration and disintegration in cooperation of states led to the creation of two integration entities – MERCOSUR and the Andean Community (AC), in the Northern subregion – NAFTA. The author concludes that the convergence on the American continent, especially using the integration method, helped to implement a special scenario in the southern part of this continent – the meta-integration scenario, with the creation of the Union of South American Nations, uniting the Andean Community and MERCOSUR – something resembling a European one, but at the same time different from it. UNASUR is an effective mechanism for bringing together and integrating the states of the South American continent. Within this Union with notable leadership of Brazil and Argentina the first steps in the direction of the foreign policy integration of the member states are traced. In terms of economic integration, the Union uses the achievements of the AC and MERCOSUR, unifying the legal regulators in the economic sphere and bringing rapprochement to the legal systems of the member states.


Oryx ◽  
1958 ◽  
Vol 4 (5) ◽  
pp. 332-334

Problems of nature preservation in British territories of central America may be clearly divided between continental countries, British Honduras and British Guiana on the one hand, and the islands on the other; although the fauna of Trinidad and Tobago has much in common with that of the South American continent. The islands of the Greater and Lesser Antilles have been separated long enough from the mainland and from each other, for them to have developed their own plants and animals. Common to continental and island countries, however, are the migratory shore birds of the western hemisphere.


2019 ◽  
Author(s):  
Jonas A. Arnemann ◽  
Stephen H. Roxburgh ◽  
Tom Walsh ◽  
Jerson V.C. Guedes ◽  
Karl H.J. Gordon ◽  
...  

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jonas Andre Arnemann ◽  
Stephen Roxburgh ◽  
Tom Walsh ◽  
Jerson Guedes ◽  
Karl Gordon ◽  
...  

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.


1960 ◽  
Vol 152 (949) ◽  
pp. 500-507 ◽  

The plant life of the southern cold temperate zone differs widely from that of the northern cold temperate zone not only in its floristic composition but also in its physiognomic types of vegetation. The latter difference is partly due to the fact that the austral zone concerned is cold temperate in a sense rather different from the corresponding boreal zone. Contrary to the great continents dominating the boreal cold temperate zone, the austral cold temperate zone consists mostly of a great ocean containing only a narrow extension of the South American continent and various islands. Owing to this difference the climates of the austral cold temperate zone are generally much more oceanic than those of the boreal cold temperate zone. Nowhere in the boreal zone do we find a climate with such small


1951 ◽  
Vol 16 (4) ◽  
pp. 354-355
Author(s):  
Gordon R. Willey

In a recent note Baerreis (1950) has given critical amplification to the question of possible cultural relations between the southeastern United States Archaic and the archaeologically known culture, or cultures, of the lower Parana River, Argentina. A paper of my own (Willey, 1949), on which Baerreis centers his discussion, focused attention on the Caribbean area and the north of the South American continent, giving only brief mention to interesting southeastern resemblances which may be found along the Parana and in the Sambaquis of southern Brazil. I agree that Baerreis has strengthened the case for cultural connections over and beyond the casual comments which I or others have offered.


1984 ◽  
Vol 3 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Frederick Burkhardt

Darwin's letters and some rough notes found in his field notebooks of 1835 confirm the statement in his Autobiography that he had formulated his theory of coral reef formation before the Beagle left South America and before he had seen a coral reef. His geological observations having convinced him of the elevation of the South American continent, Darwin predicted that evidence of a compensatory gradual subsidence of the Pacific Ocean floor would be found in the existence of shallow-water coral genera in the Pacific reef formations. The first draft of the theory was written on board the Beagle shortly after seeing the reefs of Moorea in November 1835. After visiting the Cocos (Keeling) Islands he wrote a summary of his view in a letter of April 1838, in which he expressed his conviction that he had found an explanation which would "put some of the facts in a more simple and connected point of view, than that in which they have hitherto been considered".


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