scholarly journals Interactions between natural selection and recombination shape the genomic landscape of introgression

2021 ◽  
Author(s):  
Maud Duranton ◽  
John Pool
Keyword(s):  
North American ◽  
African Ancestry ◽  
North American Population ◽  
Evolutionary Forces ◽  
The North ◽  
Genome Wide ◽  
Genomic Landscape ◽  
The One ◽  
The Relationship ◽  
Genomic Patterns

AbstractHybridization between lineages that have not reached complete reproductive isolation appears more and more like a common phenomenon. Indeed, speciation genomics studies have now extensively shown that many species’ genomes have hybrid ancestry. However, genomic patterns of introgression are often heterogeneous across the genome. In many organisms, a positive correlation between introgression levels and recombination rate has been observed. It is usually explained by the purging of deleterious introgressed material due to incompatibilities. However, the opposite relationship was observed in a North American population of Drosophila melanogaster with admixed European and African ancestry. In order to explore how directional and epistatic selection can impact the relationship between introgression and recombination, we performed forward simulations of whole D. melanogaster genomes reflecting the North American population’s history. Our results revealed that the simplest models of positive selection often yield negative correlations between introgression and recombination such as the one observed in D. melanogaster. We also confirmed that incompatibilities tend to produce positive introgression-recombination correlations. And yet, we identify parameter space under each model where the predicted correlation is reversed. These findings deepen our understanding of the evolutionary forces that may shape patterns of ancestry across genomes, and they strengthen the foundation for future studies aimed at estimating genome-wide parameters of selection in admixed populations.

scholarly journals A Risk-Based Approach to Assess the Operational Resilience of Transmission Grids

2020 ◽  
Vol 10 (14) ◽  
pp. 4761
Author(s):  
Milorad Papic ◽  
Svetlana Ekisheva ◽  
Eduardo Cotilla-Sanchez
Keyword(s):  
Power System ◽  
North American ◽  
Response Times ◽  
Transmission System ◽  
Energy Delivery ◽  
The North ◽  
System Components ◽  
Bulk Power ◽  
Definition Of ◽  
The Relationship

Modern risk analysis studies of the power system increasingly rely on big datasets, either synthesized, simulated, or real utility data. Particularly in the transmission system, outage events have a strong influence on the reliability, resilience, and security of the overall energy delivery infrastructure. In this paper we analyze historical outage data for transmission system components and discuss the implications of nearby overlapping outages with respect to resilience of the power system. We carry out a risk-based assessment using North American Electric Reliability Corporation (NERC) Transmission Availability Data System (TADS) for the North American bulk power system (BPS). We found that the quantification of nearby unscheduled outage clusters would improve the response times for operators to readjust the system and provide better resilience still under the standard definition of N-1 security. Finally, we propose future steps to investigate the relationship between clusters of outages and their electrical proximity, in order to improve operator actions in the operation horizon.

scholarly journals The effects of geographic range size and abundance on extinction during a time of “sluggish”’ evolution

Paleobiology ◽  
2020 ◽  
pp. 1-14
Author(s):  
Michelle M. Casey ◽  
Erin E. Saupe ◽  
Bruce S. Lieberman
Keyword(s):  
North American ◽  
Fossil Record ◽  
Extinction Risk ◽  
Geographic Range ◽  
Range Size ◽  
Late Paleozoic ◽  
The North ◽  
Geographic Range Size ◽  
The Relationship ◽  
Habitat Tracking

Abstract Geographic range size and abundance are important determinants of extinction risk in fossil and extant taxa. However, the relationship between these variables and extinction risk has not been tested extensively during evolutionarily “quiescent” times of low extinction and speciation in the fossil record. Here we examine the influence of geographic range size and abundance on extinction risk during the late Paleozoic (Mississippian–Permian), a time of “sluggish” evolution when global rates of origination and extinction were roughly half those of other Paleozoic intervals. Analyses used spatiotemporal occurrences for 164 brachiopod species from the North American midcontinent. We found abundance to be a better predictor of extinction risk than measures of geographic range size. Moreover, species exhibited reductions in abundance before their extinction but did not display contractions in geographic range size. The weak relationship between geographic range size and extinction in this time and place may reflect the relative preponderance of larger-ranged taxa combined with the physiographic conditions of the region that allowed for easy habitat tracking that dampened both extinction and speciation. These conditions led to a prolonged period (19–25 Myr) during which standard macroevolutionary rules did not apply.

scholarly journals Genome-wide sequence-based genotyping supports a nonhybrid origin of Castanea alabamensis

2019 ◽  
Author(s):  
M. Taylor Perkins ◽  
Tetyana Zhebentyayeva ◽  
Paul H. Sisco ◽  
J. Hill Craddock
Keyword(s):  
North American ◽  
Distinct Group ◽  
Morphological Diversity ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Eastern United States ◽  
The North ◽  
Snp Data ◽  
Genome Wide ◽  
Conservation Concern

AbstractThe genus Castanea in North America contains multiple tree and shrub taxa of conservation concern. The two species within the group, American chestnut (Castanea dentata) and chinquapin (C. pumila sensu lato), display remarkable morphological diversity across their distributions in the eastern United States and southern Ontario. Previous investigators have hypothesized that hybridization between C. dentata and C. pumila has played an important role in generating morphological variation in wild populations. A putative hybrid taxon, Castanea alabamensis, was identified in northern Alabama in the early 20th century; however, the question of its hybridity has been unresolved. We tested the hypothesized hybrid origin of C. alabamensis using genome-wide sequence-based genotyping of C. alabamensis, all currently recognized North American Castanea taxa, and two Asian Castanea species at >100,000 single-nucleotide polymorphism (SNP) loci. With these data, we generated a high-resolution phylogeny, tested for admixture among taxa, and analyzed population genetic structure of the study taxa. Bayesian clustering and principal components analysis provided no evidence of admixture between C. dentata and C. pumila in C. alabamensis genomes. Phylogenetic analysis of genome-wide SNP data indicated that C. alabamensis forms a distinct group within C. pumila sensu lato. Our results are consistent with the model of a nonhybrid origin for C. alabamensis. Our finding of C. alabamensis as a genetically and morphologically distinct group within the North American chinquapin complex provides further impetus for the study and conservation of the North American Castanea species.

scholarly journals Relationship Among Breeding, Molting, and Wintering Areas of Male Barrow's Goldeneyes (Bucephala Islandica) in Eastern North America

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 676-684 ◽  
Author(s):  
Michel Robert ◽  
Réjean Benoit ◽  
Jean-Pierre L. Savard
Keyword(s):  
North American ◽  
River Estuary ◽  
North American Population ◽  
American Population ◽  
Adult Males ◽  
Breeding Area ◽  
The North ◽  
Bucephala Islandica ◽  
The Mean ◽  
St Lawrence River

Abstract Little is known of the eastern North American population of Barrow's Goldeneyes (Bucephala islandica), which was recently listed as “of special concern” in Canada. In 1998 and 1999, we marked 18 adult males wintering along the St. Lawrence River, Québec, with satellite transmitters to document their breeding, molting, and wintering distribution and phenology, and to describe timing and routes of their spring, molt, and fall migrations. Thirteen males moved inland from the St. Lawrence River to breed; the spring migration averaged 5.9 days, and birds arrived on breeding areas on average 9 May. All breeding areas were inland, on the north shore of the St. Lawrence River estuary and gulf. Breeding areas averaged 64.8 km from the St. Lawrence corridor. Males stayed on their respective breeding area a mean of 34.5 days, and left on average 11 June. Twelve males were tracked to their molting areas, one of which stayed on its wintering area until 5 June and flew directly to its molting area. Their molt migration averaged 18.6 days, and the mean arrival date on molting areas was 30 June. All molting areas were located north and averaged 986 km from breeding areas. Four males molted in Hudson Bay, four in Ungava Bay, two in northern Labrador, one on Baffin Island, and one inland, near the Québec–Labrador border. The mean length of stay on the molting areas was 105.3 days, and the mean date of departure from molting areas was 4 October. All goldeneyes for which the radio still functioned during fall migration returned to winter in the St. Lawrence River estuary, on average 6 November. Our results refute the idea that the main breeding area of the eastern North American population of Barrow's Goldeneyes is located in northern Québec and Labrador and rather indicate that it is in the boreal forest just north of the St. Lawrence River estuary and gulf. They also indicate that Barrow's Goldeneye males undertake a genuine molt migration, and highlight the importance of molting areas because birds stayed there approximately four months each year.

Larvae of the North American Olethreutidae (Lepidoptera)

1959 ◽  
Vol 91 (S10) ◽  
pp. 5-338 ◽  
Author(s):  
Margaret Rae MacKay
Keyword(s):  
North American ◽  
Fruit Trees ◽  
Individual Species ◽  
The North ◽  
The Family ◽  
Late Instar ◽  
Species Groups ◽  
Relationship Of ◽  
Spruce Needles ◽  
The Relationship

AbstractThe late-instar larvae of about 185 species of the North American Olethreutidae are described and most of them illustrated. Included in these are many pests, such as Grapholitha molesta, Carpocapsa pomonella, and Spilonota ocellana on fruit trees, Paralobesia viteana on grapes, Ancylis comptana fragariae on strawberries, Laspeyresia nigricana in pea pods, Laspeyresia caryana in hickory and pecan nuts, Taniva albolineana in spruce needles, and species of Rhyacionia and Petrova on pines. Keys to species groups and to individual species are provided. Of the diagnostic and specialized characters listed, the most useful include the setae, the spinneret, and the shape of the larva, especially of its head and anal shield. The main characters are given for the postulated ancestral larva and for the highly developed larva. Most of the species groups are arranged according to the suggested phylogenetic relationship of their larvae, emphasizing the necessity of a revision of the family. Larvae of some genera previously difficult to classify, such as Pseudogalleria and Hystricophora, indicate the relationship of those genera to other groups; conversely, lack of relationship is clearly shown in other instances, e.g., between Carpocapsa pomonella and Carpocapsa saltitans, and between the two species Epiblema culminana and E. suffusana and other members of the genus Epiblema.

A New Species of Glenanthe Haliday (Diptera: Ephydridae) from the North American Interior

1964 ◽  
Vol 96 (5) ◽  
pp. 811-812 ◽  
Author(s):  
J. G. Chillcott
Keyword(s):  
New Species ◽  
North American ◽  
Sand Dunes ◽  
Wing Pattern ◽  
Lake Agassiz ◽  
The North ◽  
Covered Area ◽  
The One ◽  
A New Species

One of the most unusual results of intensive collecting in southern Manitoba in. 1958 was the discovery of this striking representative of a dominantly coastal genus of Ephydridae. It ivas collected at several times but in only the one locality, the Bald Head Hills, a region of active sand dunes in the largely stabilized, spruce-covered area representing the shores of the Pleistocene Lake Agassiz. The species is strikingly different from other species of the genus in its thoracic and wing pattern, hut in structural characters it is fairly typical.

INTERESSES PROVINCIAIS NO BRASIL NOS ANOS DA GUERRA CIVIL NORTE-AMERICANA: uma mirada transnacional sobre relações entre o Império e as Prová­ncias

2019 ◽  
Vol 16 (27) ◽  
pp. 276-299
Author(s):  
JULIANA JARDIM DE OLIVEIRA E OLIVEIRA
Keyword(s):  
Civil War ◽  
North American ◽  
International Perspective ◽  
American Civil War ◽  
Cotton Production ◽  
National State ◽  
International Context ◽  
The North ◽  
Lower House ◽  
The Relationship

Este artigo aborda o tema das relações entre Império e Prová­ncias no Brasil a partir de um olhar internacional e em um contexto de ”crise da década de 1860” e da Guerra Civil nos EUA. Dentro do contexto de uma guerra que tem implicações transnacionais, analisaremos dois focos de debate na Cá¢mara dos Deputados do Brasil que sofreram a influência do conflito nos EUA: as propostas de retomada de produção do algodão e os problemas relativos ao recrutamento de soldados em meio á  guerra. Busca-se demonstrar que a Cá¢mara dos Deputados foi palco importante para que os deputados se posicionassem a partir de diferentes interesses regionais ou provinciais, frente a um contexto internacionalizado. Em suas falas é possá­vel observar que em face ao conflito norte-americano e o contexto internacional, os parlamentares foram capazes de fazer uso de um ”jogo de escalas” para discutirem demandas e interesses regionais, explicitando relações nacionais, regionais e internacionais.Palavras-chave:  Estado Nacional. Guerra Civil. Prová­ncias.  PROVINCIAL INTERESTS IN BRAZIL DURING THE AMERICAN CIVIL WAR:  a transnational view of the relationship between the Empire and the ProvincesAbstract:  This paper discusses the relationship between the Empire as a central power and the Provinces in Brazil from an international perspective within the context of the ”crisis of the 1860s” and the American Civil War. In view of this national conflict with transnational implications, we will focus on two debates in the Brazilian Lower House of Congress: the debates over the investments in cotton production and the army recruitment in times of war. The Lower House was an important environment for Brazilian Congressmen to defend different regional or provincial demands, in view of an internationalized context. In their speeches it is possible to assert that, when faced with the North American conflict and the international context, congressmen were able to use a game of ”scales” to expose their regional demands and interests, highlighting national, regional, and international relationships.Keywords:  Civil War. National State. Provinces.  INTERESES PROVINCIALES EN BRASIL EN LOS Aá‘OS DE LA GUERRA CIVIL NORTEAMERICANA:  una mirada transnacional sobre relaciones entre el Imperio y las ProvinciasResumen:  Este articulo trata del tema de las relaciones entre imperio y provincias de Brasil a partir de la mirada internacional en el contexto de la ”crisis de la década de 1860” y de la Guerra Civil de los EEUU. Dentro del contexto de una guerra de carácter internacional, analizaremos dos enfoques de debate en la Cámara de los Diputados de Brasil: las propuestas de retomadas en la producción del algodón y los problemas relacionados al reclutamiento de soldados en el medio de la guerra. Es objetivo probar que la Cámara de los Diputados fue un escenario importante para que los diputados se posicionaran a partir de diferentes intereses regionales o provinciales, frente a un contexto internacionalizado. En sus declaraciones es posible observar que ante el conflicto norteamericano y el contexto internacional, los parlamentarios fueron capaces de hacer uso de un ”juego de escalas” para discutir demandas e intereses regionales, explicitando relaciones nacionales, regionales e internacionales.Palabras clave:  Estado Nacional. Guerra Civil. Provincias.

scholarly journals Normative Data for the Stroop Color Word Test for a North American Population

2013 ◽  
Vol 40 (6) ◽  
pp. 842-847 ◽  
Author(s):  
Sarah A. Morrow
Keyword(s):  
North American ◽  
Processing Speed ◽  
Normative Data ◽  
North American Population ◽  
Attentional Deficits ◽  
Word Test ◽  
The North ◽  
Colour Word ◽  
Impaired Attention ◽  
Serial Addition

Background:Cognitive impairment in multiple sclerosis (MS) often involves attentional deficits. The Stroop colour word test, a measure of attention, lacks current normative data for an english-speaking North american MS population. Further some authors suggest the Stroop actually measures processing speed.Objective:To generate normative data for the Stroop colour word test that can be used for a Canadian or North american MS population and to examine the relationship between processing speed tests - the Paced auditory Serial addition Test (PASAT) and Symbol Digit Modalities Test (SDMT) - and the Stroop.Results:Data from 146 healthy subjects aged 18-56 was collected. age was significantly although weakly correlated with general intelligence (r=0.168, p=0.043) assessed with the North american adult Reading Test (NAART), and education (r=-0.313, p<0.001). No demographic variables were associated with SDMT or PASAT. age had a low-moderate negative correlation (r=-0.403, p<0.001) with Stroop scores. The mean (±standard deviation, SD) Stroop score was 45.4(10.4). The z-score can thus be calculated as [(X-45.4)/10.4]. if adjusted for age, Xadj = [X-(-0.47)(age-37.5)] and is substituted for X. in a comparison MS population consisting of 75 randomly selected patients from the MS Cognitive clinic, Stroop and PASAT performance were not related. a relationship existed between Stroop and SDMT scores but only 12.2% of the Stroop score variance was explained by the SDMT. Therefore, the Stroop measures selective attention independently of processing speed.Conclusion:This data can be used to determine impaired attention in MS patients.

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