scholarly journals Historical and Contemporary Diversity of Galaxiids in South America: Biogeographic and Phylogenetic Perspectives

Diversity ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 304 ◽  
Author(s):  
Iván Vera-Escalona ◽  
M. Lisette Delgado ◽  
Evelyn Habit ◽  
Daniel E. Ruzzante
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Human Activity ◽  
Glacial Refugia ◽  
Glacial Ice ◽  
The Pacific ◽  
Genetic Patterns ◽  
Native Fishes ◽  
Freshwater Fauna ◽  
Impacts Of Human Activity

Galaxiid fishes from South America are represented by three genera (Aplochiton, Brachygalaxias and Galaxias) and eight species. Their genetic patterns have been studied over the last two decades to disentangle how historical and contemporary processes influenced their biogeographic distribution and phylogeographic patterns. Here we review and synthesize this body of work. Phylogeographic approaches reveal the important role played by orogeny and the expansion/melting of glacial ice during the Quaternary. Populations retreated to glacial refugia during glacial times and some systems experienced drainage reversals from the Atlantic to the Pacific following deglaciation. Although most species expanded their populations and increased their genetic diversity during the Holocene, the introduction of salmonids and the construction of dams are likely to lead to a decline in genetic diversity for at least some species. An improvement in our understanding of the processes that influenced historical and contemporary diversity patterns among galaxiid and other native fishes in South America is necessary for addressing the cumulative and synergistic impacts of human activity on this unique freshwater fauna.

scholarly journals European and Asian contribution to the genetic diversity of mainland South American chickens

2020 ◽  
Vol 7 (2) ◽  
pp. 191558 ◽  
Author(s):  
Michael B. Herrera ◽  
Spiridoula Kraitsek ◽  
Jose A. Alcalde ◽  
Daniel Quiroz ◽  
Herman Revelo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Southeast Asia ◽  
Fifteenth Century ◽  
Control Region ◽  
Pacific Islands ◽  
Mitochondrial Control Region ◽  
South American ◽  
Island Southeast Asia ◽  
The Pacific

Chickens ( Gallus gallus domesticus ) from the Americas have long been recognized as descendants of European chickens, transported by early Europeans since the fifteenth century. However, in recent years, a possible pre-Columbian introduction of chickens to South America by Polynesian seafarers has also been suggested. Here, we characterize the mitochondrial control region genetic diversity of modern chicken populations from South America and compare this to a worldwide dataset in order to investigate the potential maternal genetic origin of modern-day chicken populations in South America. The genetic analysis of newly generated chicken mitochondrial control region sequences from South America showed that the majority of chickens from the continent belong to mitochondrial haplogroup E. The rest belongs to haplogroups A, B and C, albeit at very low levels. Haplogroup D, a ubiquitous mitochondrial lineage in Island Southeast Asia and on Pacific Islands is not observed in continental South America. Modern-day mainland South American chickens are, therefore, closely allied with European and Asian chickens. Furthermore, we find high levels of genetic contributions from South Asian chickens to those in Europe and South America. Our findings demonstrate that modern-day genetic diversity of mainland South American chickens appear to have clear European and Asian contributions, and less so from Island Southeast Asia and the Pacific Islands. Furthermore, there is also some indication that South Asia has more genetic contribution to European chickens than any other Asian chicken populations.

scholarly journals Genome-wide diversity of coconut from northern South America uncovers genotypes present in Colombia and strong population structure

2019 ◽  
Author(s):  
Jorge Mario Muñoz-Pérez ◽  
Gloria Patricia Cañas ◽  
Lorena López ◽  
Tatiana Arias
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
South America ◽  
Genetic Relationships ◽  
Cocos Nucifera ◽  
Principal Component ◽  
Nucleotide Polymorphisms ◽  
The Pacific ◽  
Population Structure Analysis ◽  
Northern South America

SummaryCoconut palms (Cocos nucifera) are a combination of wild admixed populations and perennial crops with a worldwide distribution. Here we develop single nucleotide polymorphisms (SNPs) along the coconut genome based on Genotyping by Sequencing (GBS) for at least four different commercially important and widely cultivated coconut varieties and hybrids growing in northern South America. We present a comprehensive catalog of approximately 27K SNPs to conduct genetic diversity, population structure and linkage disequilibrium analysis. A relatively fast LD decay for the Atlantic accessions within ~250Kb was observed in comparison to the Pacific accessions ~ 1500 Kb.The complete SNPs sampling showed a strong population structure at K = 2, separating accessions from the Pacific and Atlantic coasts as it has been found in previous studies. At higher K values, one non-admixed group was observed for the Atlantic while further substructures emerged for the Pacific accessions, where three non-admixed groups were found. Population structure analysis also showed a great degree of admixture between the Atlantic and Pacific populations, and SNPs of the Pacific non-admixed genetic groups were mostly introgressed into the Atlantic individuals but the contrary was rarely observed. The results of principal component analysis and Neighbor-Joining Hierarchical Clustering were consistent with the results from Structure and provided a measure of genetic relationships among individual genotypes. The Pacific group has a lower genetic diversity and a higher rate of inbreeding than the Atlantic group. These results suggest that the Pacific coconuts of Colombia belong to the pre-Columbian population found on the Pacific coast of Panama and Peru. If it had been introduced after Columbus (as in Mexico), genetic diversity would have been higher than on the Atlantic coast.

scholarly journals Influence of environmental factors on the genetic variation of the aquatic macrophyte Ranunculus subrigidus on the Qinghai-Tibetan Plateau

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhigang Wu ◽  
Xinwei Xu ◽  
Juan Zhang ◽  
Gerhard Wiegleb ◽  
Hongwei Hou
Keyword(s):  
Genetic Diversity ◽  
Tibetan Plateau ◽  
Environmental Factors ◽  
Local Adaptation ◽  
Aquatic Macrophyte ◽  
Spatial Genetic Structure ◽  
Long Distance ◽  
Elevation Gradients ◽  
Mantel Tests ◽  
Genetic Patterns

Abstract Background Due to the environmental heterogeneity along elevation gradients, alpine ecosystems are ideal study objects for investigating how ecological variables shape the genetic patterns of natural species. The highest region in the world, the Qinghai-Tibetan Plateau, is a hotspot for the studies of evolutionary processes in plants. Many large rivers spring from the plateau, providing abundant habitats for aquatic and amphibious organisms. In the present study, we examined the genetic diversity of 13 Ranunculus subrigidus populations distributed throughout the plateau in order to elucidate the relative contribution of geographic distance and environmental dissimilarity to the spatial genetic pattern. Results A relatively low level of genetic diversity within populations was found. No spatial genetic structure was suggested by the analyses of molecular variance, Bayesian clustering analysis and Mantel tests. Partial Mantel tests and multiple matrix regression analysis showed a significant influence of the environment on the genetic divergence of the species. Both climatic and water quality variables contribute to the habitat heterogeneity of R. subrigidus populations. Conclusions Our results suggest that historical processes involving long-distance dispersal and local adaptation may account for the genetic patterns of R. subrigidus and current environmental factors play an important role in the genetic differentiation and local adaptation of aquatic plants in alpine landscapes.

scholarly journals Genetic diversity and kinship relationships in one of the largest South American fur seal ( Arctocephalus australis ) populations of the Pacific Ocean

2021 ◽  
Author(s):  
Josefina Gutiérrez ◽  
Mauricio Seguel ◽  
Pablo Saenz‐Agudelo ◽  
Gerardo Acosta‐Jamett ◽  
Claudio Verdugo
Keyword(s):  
Genetic Diversity ◽  
Pacific Ocean ◽  
South American ◽  
The Pacific ◽  
Fur Seal ◽  
The Pacific Ocean

Overt and Concealed Genetic Loads Revealed by QTL Mapping of Genotype-dependent Viability in the Pacific Oyster Crassostrea gigas

Genetics ◽  
2021 ◽  
Author(s):  
Xiaoshen Yin ◽  
Dennis Hedgecock
Keyword(s):  
Genetic Diversity ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Genetic Load ◽  
High Density ◽  
High Genetic Diversity ◽  
High Fecundity ◽  
Recessive Mutations ◽  
Genotype Frequencies ◽  
The Pacific

Abstract Understanding the genetic bases of inbreeding depression, heterosis, and genetic load is integral to understanding how genetic diversity is maintained in natural populations. The Pacific oyster Crassostrea gigas, like many long-lived plants, has high fecundity and high early mortality (type-III survivorship), manifesting a large, overt, genetic load; the oyster harbors an even greater concealed genetic load revealed by inbreeding. Here, we map viability QTL (vQTL) in six interrelated F2 oyster families, using high-density linkage maps of single nucleotide polymorphisms generated by genotyping-by-sequencing (GBS) methods. Altogether, we detect 70 vQTL and provisionally infer 89 causal mutations, 11 to 20 per family. Genetic mortality caused by independent (unlinked) vQTL ranges from 94.2% to 97.8% across families, consistent with previous reports. High-density maps provide better resolution of genetic mechanisms, however. Models of one causal mutation present in both identical-by-descent (IBD) homozygotes and heterozygotes fit genotype frequencies at 37 vQTL; consistent with the mutation-selection balance theory of genetic load, 20 are highly deleterious, completely recessive mutations and 17 are less deleterious, partially dominant mutations. Another 22 vQTL require pairs of recessive or partially dominant causal mutations, half showing selection against recessive mutations linked in repulsion, producing pseudo-overdominance. Only eight vQTL appear to support the overdominance theory of genetic load, with deficiencies of both IBD homozygotes, but at least four of these are likely caused by pseudo-overdominance. Evidence for epistasis is absent. A high mutation rate, random genetic drift, and pseudo-overdominance may explain both the oyster’s extremely high genetic diversity and a high genetic load maintained primarily by mutation-selection balance.

Past Sea Surface Temperature of the Pacific Ocean of South America a Reference for Environmental Archeology

2022 ◽  
Author(s):  
Hector Luis D’Antoni ◽  
Lidia Susana Burry ◽  
Patricia Irene Palacio ◽  
Matilde Elena Trivi ◽  
Mariano Somoza
Keyword(s):  
Pacific Ocean ◽  
South America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
The Pacific ◽  
The Pacific Ocean

scholarly journals Divergence time estimations and contrasting patterns of genetic diversity between Antarctic and southern South America benthic invertebrates

2012 ◽  
Vol 85 (4) ◽  
pp. 445-456 ◽  
Author(s):  
CLAUDIO ALEJANDRO GONZÁLEZ-WEVAR ◽  
ANGIE DÍAZ ◽  
KARIN GERARD ◽  
JUAN IVÁN CAÑETE ◽  
ELIE POULIN
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Benthic Invertebrates ◽  
Divergence Time ◽  
Southern South America

Confronting a Mercantile Elite: Bourbon Reformers and the Merchants of Lima, 1765–1796

2004 ◽  
Vol 60 (04) ◽  
pp. 519-558
Author(s):  
Patricia H. Marks
Keyword(s):  
South America ◽  
Pacific Coast ◽  
Point Of View ◽  
Economic Effects ◽  
Port City ◽  
Tax Reforms ◽  
Positive Effects ◽  
Colonial Peru ◽  
The Pacific ◽  
Significant Change

After Spain’s defeat in the Seven Years’ War (1757-1763), when the British had occupied Havana and Manila, a series of territorial, commercial, and tax reforms brought significant change to the viceroyalty of Peru. Their economic effects have been matters for debate ever since. Some historians have emphasized their positive effects. Following promulgation of the Reglamento de comercio libre of 1778, the volume and value of European manufactures exported to the Pacific coast of Spanish South America increased. Lima and its port city, Callao, remained important as commercial centers of Spanish South America. But others suggest that the viceregal capital—home to a powerful mercantile elite, the magnates of the consulado (merchant guild) of Lima—suffered a decline in its economic fortunes, as did the entire viceroyalty. Support for this point of view was widespread in late colonial Peru. In spite of the evidence for growth, a rising chorus of complaint bemoaned the increasing poverty of the viceroyalty in general and Lima in particular. How can we account for this discrepancy?

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