768 resultados para BIOGEOGRAPHICAL ANCESTRY
Resumo:
Background - The PCK1 gene, encoding cytosolic phosphoenolpyruvate carboxykinase (PEPCKC), has previously been implicated as a candidate gene for type 2 diabetes (T2D) susceptibility. Rodent models demonstrate that over-expression of Pck1 can result in T2D development and a single nucleotide polymorphism (SNP) in the promoter region of human PCK1 (-232C/G) has exhibited significant association with the disease in several cohorts. Within the UK-resident South Asian population, T2D is 4 to 6 times more common than in indigenous white Caucasians. Despite this, few studies have reported on the genetic susceptibility to T2D in this ethnic group and none of these has investigated the possible effect of PCK1 variants. We therefore aimed to investigate the association between common variants of the PCK1 gene and T2D in a UK-resident South Asian population of Punjabi ancestry, originating predominantly from the Mirpur area of Azad Kashmir, Pakistan. Methods - We used TaqMan assays to genotype five tagSNPs covering the PCK1 gene, including the -232C/G variant, in 903 subjects with T2D and 471 normoglycaemic controls. Results - Of the variants studied, only the minor allele (G) of the -232C/G SNP demonstrated a significant association with T2D, displaying an OR of 1.21 (95% CI: 1.03 - 1.42, p = 0.019). Conclusion - This study is the first to investigate the association between variants of the PCK1 gene and T2D in South Asians. Our results suggest that the -232C/G promoter polymorphism confers susceptibility to T2D in this ethnic group.
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Background - Recent studies have implicated variants of the transcription factor 7-like 2 (TCF7L2) gene in genetic susceptibility to type 2 diabetes mellitus in several different populations. The aim of this study was to determine whether variants of this gene are also risk factors for type 2 diabetes development in a UK-resident South Asian cohort of Punjabi ancestry. Methods - We genotyped four single nucleotide polymorphisms (SNPs) of TCF7L2 (rs7901695, rs7903146, rs11196205 and rs12255372) in 831 subjects with diabetes and 437 control subjects. Results - The minor allele of each variant was significantly associated with type 2 diabetes; the greatest risk of developing the disease was conferred by rs7903146, with an allelic odds ratio (OR) of 1.31 (95% CI: 1.11 – 1.56, p = 1.96 × 10-3). For each variant, disease risk associated with homozygosity for the minor allele was greater than that for heterozygotes, with the exception of rs12255372. To determine the effect on the observed associations of including young control subjects in our data set, we reanalysed the data using subsets of the control group defined by different minimum age thresholds. Increasing the minimum age of our control subjects resulted in a corresponding increase in OR for all variants of the gene (p ≤ 1.04 × 10-7). Conclusion - Our results support recent findings that TCF7L2 is an important genetic risk factor for the development of type 2 diabetes in multiple ethnic groups.
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East-Christian icon art is recognised as one of the most significant areas of the art of painting. Regrettably, it is still being neglected in the digital documentation and the registry of the art of painting. The accessibility to that large part of mankind's cultural and historical ancestry would be enhanced greatly if icons of all possible kinds and origins were digitised, classified, and „exhibited“ in the Internet. That would allow the preservation and even the future digital restoration of a large number of rare specimens of the East-Christian art of painting. This article aims to introduce how modern techniques from the area of digital libraries can be used for implementing the demonstrative multimedia library “Virtual encyclopaedia of the Bulgarian iconography ” 4, containing a large number of Bulgarian iconic art masterpieces and iconography of various authors, periods and schools.
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Immigrants from the West Indies and other nations challenge the simple United States dichotomy of blacks versus whites. Many apparently black Caribbean immigrants proclaim that they did not know they were “black” until they arrived in the U.S. They seek to maintain their national identity and resist identity and solidarity with Black Americans. In response, many Black Americans respond that the immigrants are simply being naive, that U.S. society demands simple racial identity. Regardless of one's self-identity and personal history, in the U.S., if you look black, you are black, was their thinking. ^ This study examines the contemporary struggle of identity and solidarity among and between Black Americans and Jamaicans living in South Florida (Broward and Miami-Dade counties). Even though the primary focus of this study is to examine the relationship between Black Americans and Jamaicans, other West Indian nationals will be addressed more generally. The primary research problem of this study is to determine why the existence of common ancestry and physical traits are insufficient for an assumption of ethnic solidarity between Black Americans and Jamaicans. ^ In examining this problem, I felt that depth rather than breadth would provide insight into the current state of polarization between Black Americans and Jamaicans. To this end, a qualitative study was designed. A non-random snowball sample consisting of forty-seven informants was selected for this study. Realizing that such a technique presents problems with generalizations beyond the sample, this approach was, nonetheless, the most suitable for the current research problem. One of the initial challenges of this research was the use of the label “black” in discussing Caribbean immigrants. Unlike America, where distinctions based on skin color were at the bedrock of America's formation, this was not the case in the Caribbean. In the Caribbean skin color was an important marker as an indicator of class, rather than of race. Therefore, I refrained from using the label, “black Jamaicans,” but rather used Jamaicans throughout. ^
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Isla del Coco (Cocos Island) is a small volcanic island located in the Pacific 500 km west of Costa Rica. Three collecting trips to Isla del Coco, in addition to herbarium research, were completed in order to assess the floristic diversity of the island. The current flora of Isla del Coco contains 262 plant species of which 37 (19.4%) are endemic. This study reports 58 species as new to the island. Seventy-one species (27.1%) were identified as introduced by humans. In addition, five potentially invasive plant species are identified. Seven vegetation types are identified on the island: bayshore, coastal cliff, riparian, low elevation humid forest, high elevation cloud forest, landslide and islet. ^ The biogeographic affinities of the native and endemic species are with Central America/northern South America and to a lesser extent, the Caribbean. Endemic species in the genus Epidendrum were investigated to determine whether an insular radiation event had produced two species found on Isla del Coco. Phylogenetic analysis of the internal transcribed spacer (ITS) of nuclear ribosomal DNA was not able to disprove that the endemic species in this genus are not sister species. Molecular biogeographic analyses of ITS sequence data determined that the Isla del Coco endemic species in the genera Epidendrum, Pilea and Psychotria are most closely related to Central American/northern South American taxa. No biogeographical links were found between the floras of Isla del Coco and the Galápagos Islands. ^ The native and endemic plant diversity of Isla del Coco is threatened with habitat degradation by introduced pigs and deer, and to a lesser extent, by exotic plant species. The IUCN Red List and RAREplants criteria were used to assess the extinction threat for the 37 endemic plant taxa found on the island. All of the endemic species are considered threatened with extinction at the Critically Endangered (CR) by the IUCN criteria or either CR or Endangered (EN) using RAREplants methodology. ^
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Dioon Lindl. (Zamiaceae) is a small genus restricted to Mexico (12 species) and Honduras (one species). Previous systematic studies have been unable to fully resolve species relationships within the genus. Phylogenetic analyses were conducted with data from several sources, including Restriction Fragment Length Polymorphisms from the chloroplast genome, morphology, two introns of the low copy nuclear gene S-adenosyl-L-homocysteine hydrolase (SAHH) and the 5.8S/ITS2 regions of the nuclear ribosomal DNA. The goals of the study were to construct a total evidence species level phylogeny and to explore current biogeographical hypotheses. None of the analyses performed produced a fully resolved topology. Dioon is comprised of two main lineages (the Edule and Spinulosum Clades), which represents an ancient divergence within the genus. The two introns of the nuclear gene SAHH offer additional evidence for the split into two lineages. Intron 2 contains a 18 bp deletion in the Spinulosum Clade, providing a synapomorphy for that group. The 5.8S/ITS2 regions were highly polymorphic and subsequently omitted from the combined analyses. In order to visualize congruence between morphology and molecular data, morphological characters were mapped onto the combined molecular tree. Current biogeographical hypotheses of a general northward pattern of migration and speciation are supported here. However, sister relationships within the Edule Clade are not fully resolved. Seven DNA microsatellite markers were developed to investigate patterns of genetic variation of seven populations of D. edule, a species restricted to Eastern Mexico. We found that most of the genetic variation lies within populations (Ho = 0.2166–0.3657) and that levels of population differentiation are low (Fst = 0.088); this finding is congruent with the breeding system of this species, dioicy. Four of the populations deviate from Hardy Weinberg Equilibrium and have a high number of identical genotypes, we suggest that this unexpected pattern is due to the life-history strategy of the species coupled with the few number of polymorphic loci detected in these populations. Our results are not congruent with earlier evidence from morphology and allozyme markers that suggest that the two northernmost populations represent a distinct entity that is recognized by some taxonomists as D. angustifolium.
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Immigrant incorporation in the United States has been a topic of concern and debate since the founding of the nation. Scholars have studied many aspects of the phenomenon, including economic, political, social, and spatial. The most influential paradigm of immigrant incorporation in the US has been, and continues to be, assimilation, and the most important place in and scale at which incorporation occurs is the neighborhood. This dissertation captures both of these integral aspects of immigrant incorporation through its consideration of three dimensions of assimilation – identity, trust, and civic engagement – among Latin American immigrants and American-born Latinos in Little Havana, a predominantly immigrant neighborhood in Miami, Florida. Data discussed in the dissertation were gathered through surveys and interviews as part of a National Science Foundation-funded study carried out in 2005-2006. The combination of quantitative and qualitative data allows for a nuanced understanding of how immigrant incorporation is occurring locally during the first decade of the twentieth century. Findings reveal that overall Latin American immigrants and their American-born offspring appear to be becoming American with regard to their ethnic and racial identities quickly, evidenced through the salience and active employment of panethnic labels, while at the same time they are actively reshaping the identificational structure. The Latino population, however, is not monolithic and is cleaved by diversity within the group, including country of origin and socioeconomic status. These same factors impede group cohesion in terms of trust and its correlate, community. Nevertheless, the historically dominant ancestry group in Little Havana – Cubans – has been able to reach notable levels of trust and build and conserve a more solid sense of community than non-Cuban residents. With respect to civic engagement, neighborhood residents generally participate at rates lower than the overall US population and ethnic subpopulations. This is not the case for political engagement, however, where self-reported voting registration and turnout in Little Havana surpasses that of most benchmarked populations. The empirical evidence presented in this dissertation on the case of Latinos in Little Havana challenges the ways that identity, trust, and civic engagement are conceptualized and theorized, especially among immigrants to the US.
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This study examines the educational persistence of women of African descent (WOAD) in pursuit of a doctorate degree at universities in the southeastern United States. WOAD are women of African ancestry born outside the African continent. These women are heirs to an inner dogged determination and spirit to survive despite all odds (Pulliam, 2003, p. 337).This study used Ellis’s (1997) Three Stages for Graduate Student Development as the conceptual framework to examine the persistent strategies used by these women to persist to the completion of their studies. Semi-structured interviews were conducted, transcribed, and analyzed for the 10 study participants. The study examined their beliefs, roles, and support systems utilized during their studies to help propel them to succeed. Interview data were analyzed using cross-case analysis to discover emerging themes and patterns. A comparative analysis was used to analyze the participants’ experiences and discover themes and patterns to review against the historical data. The findings showed that WOAD experienced feelings of isolation, neglect and racial prejudice as doctoral students. Their ability to formulate supportive relationships among each other and in their communities outside the university was key to their persistence to graduation. There still remains a need to create a more engaging and inclusive environment for nontraditional students, particularly those who are WOAD. The study concludes with six strategies of success used by these WOAD to persist to completion. Those six strategies include 1. Keeping the goal of earning a doctorate and graduating foremost on your mind. 2. Set a class and study schedule that allows you to balance family, work and study. 3. Take care of yourself, physically, mentally and emotionally. 4. Keep a goal chart to track your strides toward completion/graduation. 5. Establish a strong support system among your family, friends, colleagues and community; and 6. Do not let the “isms” (racism, sexism, and ageism) deter you.
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The Caribbean Island Biodiversity Hotspot is the largest insular system of the New World and a priority for biodiversity conservation worldwide. The tribe Adeliae (Euphorbiaceae) has over 35 species endemic to this hotspot, representing one of the most extraordinary cases of speciation in the West Indies, involving taxa from Cuba, Hispaniola, Jamaica, and the Bahamas. These species form a monophyletic group and traditionally have been accommodated in two endemic genera: Lasiocroton and Leucocroton. A study based on: (1) scanning electron microscopy of pollen and trichomes, (2) macromorphology, and (3) molecular data, was conducted to reveal generic relationships within this group. Phylogenies were based on parsimony and Bayesian analyses of nucleotide sequences of the ITS regions of the nuclear ribosomal DNA and the non-coding chloroplast DNA spacers psbM-trnD and ycf6-pcbM. One species, Lasiocroton trelawniensis, was transferred from the tribe into the genus Bernardia. Of the remaining species, three major monophyletic assemblages were revealed, one was restricted to limestone ares of Hispaniola and was sister to a clade with two monophyletic genera, Lasiocroton and Leucocroton. Morphological, biogeographical, and ecological data provided additional support for each of these three monophyletic assemblages. The Hispaniolan taxa were accommodated in a new genus with four species: Garciadelia. Leucocroton includes the nickel hyperaccumulating species from serpentine soils of Cuba, while the rest of the species were placed in Lasiocroton, a genus restricted to limestone areas. The geographic history of the islands as well as the phylogenetic placement of the Leucocroton-alliance, allows the research to include the historical biogeography of the alliance across the islands of the Caribbean based on a dispersal-vicariance analysis. The alliance arose on Eastern Cuba and Hispaniola, with Lasiocroton and Leucocroton diverging on Eastern Cuba according to soil type. Within Leucocroton, the analysis shows two migrations across the serpentine soils of Cuba. Additional morphological, ecological, and phylogenetic analyses support four new species in Cuba (Lasiocroton gutierrezii) and Hispaniola ( Garciadelia abbottii, G. castilloae, and G. mejiae). ^
Resumo:
During the past 500 years, the Bahamas has been influenced by a wide array of settlers, including but not limited to, the Arawak Indians, Eleutherian Adventurers, British Loyalists, Creole slaves, liberated Africans as well as Chinese, Greek, Jewish, Lebanese, Jamaican and Haitian migrants. To date, however, only a few reports analyzing the genetic makeup and population dynamics of the Bahamas have been published, making this work pivotal in the endeavor to ascertain the genetic ancestry of these groups. As such, the current investigation was undertaken to genetically characterize six of the more densely populated islands throughout the Northwest (Grand Bahama and Abaco) and Central (Eleuthera, Exuma, Long Island and New Providence) Bahamas using different forensic marker systems. When autosomal STR markers are employed, the Bahamian collections were all found to receive differential contributions from the African, European, East Asian and Native American collections utilized in the analyses. Similar findings were also observed for two other Afro-Caribbean populations, Haiti and Jamaica, although the latter populace was found to share a greater proportion of its autosomal component with non-African sources than the former. On the contrary, analysis of the six Bahamian collections using high-resolution Y-chromosome markers identifies genetic signals emanating exclusively from Africans and Europeans, but this is likely the result of smaller sample sizes collected from each island and/or sex-biased gene flow from East Asian and Native American groups.
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This study assessed the civic knowledge, skills, and attitudes of Hispanic eighth grade students in Miami-Dade County Public Schools (M-DCPS), Florida. Three hundred sixty one Hispanic students of Cuban (253), Colombian (57), and Nicaraguan (51) ancestry from 10 middle schools participated in the study. Two hundred twenty eight students were from low socio-economic status (SES) background, and 133 were of middle SES background. There were 136 boys and 225 girls. The International Association for the Evaluation of Educational Achievement Civic Education Student Questionnaire was used to collect data. The instrument assessed the students’ civic knowledge, skills, and attitudes. Multivariate analysis of variance was used to test for differences in the civic knowledge, skills, and attitudes of participants based on ancestry, SES, and gender. ^ The findings indicated that there was no significant difference in the civic knowledge, skills, and attitudes of Hispanic eighth grade students that were of Cuban, Colombian, and Nicaraguan ancestry. There was no significant difference in the civic skills and in five of the civic attitude scales for students from low SES families compared to those from middle SES families. However, there was a significant difference in the civic knowledge and in the civic attitude concerning classroom discussions and participation based on SES. The civic knowledge of middle SES students was higher than that of low SES students. Furthermore, middle SES Hispanic students displayed a higher mean score for the civic attitude of classroom discussions and participation than low SES students. There was no significant difference in the civic knowledge and in five of the civic attitude scales between boys and girls. However, there was a significant difference in the civic skills and the civic attitude of support for women’s rights between boys and girls. Hispanic girls displayed a higher mean score in civic skills than Hispanic boys. Furthermore, the mean score of civic attitude of support for women’s rights for Hispanic girls was higher than that of Hispanic boys. ^ It was concluded that Cuban, Colombian, or Nicaraguan participants did not demonstrate differences in civic attitudes and levels of civic knowledge and skills that eighth grade students possessed. In addition, when compared to boys, girls demonstrated a higher level of civic skills and a greater support for women’s rights and participation in politics and their roles in politics. Moreover, SES was demonstrated to be a key factor in the acquisition of civic knowledge, regardless of ancestry.^
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A set of 40 Uranium-series datings obtained on the reef-forming scleractinian cold-water corals Lophelia pertusa and Madrepora oculata revealed that during the past 400 kyr their occurrence in the Gulf of Cádiz (GoC) was almost exclusively restricted to glacial periods. This result strengthens the outcomes of former studies that coral growth in the temperate NE Atlantic encompassing the French, Iberian and Moroccan margins dominated during glacial periods, whereas in the higher latitudes (Irish and Norwegian margins) extended coral growth prevailed during interglacial periods. Thus it appears that the biogeographical limits for sustained cold-water coral growth along the NE Atlantic margin are strongly related to climate change. By focussing on the last glacial-interglacial cycle, this study shows that palaeo-productivity was increased during the last glacial. This was likely driven by the fertilisation effect of an increased input of aeolian dust and locally intensified upwelling. After the Younger Dryas cold event, the input of aeolian dust and productivity significantly decreased concurrent with an increase in water temperatures in the GoC. This primarily resulted in reduced food availability and caused a widespread demise of the formerly thriving coral ecosystems. Moreover, these climate induced changes most likely caused a latitudinal shift of areas withoptimum coral growth conditions towards the northern NE Atlantic where more suitable environmental conditions established with the onset of the Holocene.
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The present data set is a registry of samples from the Tara Oceans Expedition (2009-2013) that were selected for publication in a special issue of the SCIENCE journal (see related references below). The registry provides details about the sampling location and methodology of each sample. Uniform resource locators (URLs) offer direct links to additional contextual environmental data and to the corresponding sequence runs used for analysis in the related literature publications in the SCIENCE journal.
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Genetic heterogeneity, lifestyle factors, gene-gene or gene-environment interactions are the determinants of T2D which puts Hispanics and populations with African ancestry at higher risk of developing T2D. In this dissertation, the genetic associations of PPARGC1A polymorphisms with T2D and its related phenotypes (metabolic markers) in Haitian Americans (cases=110, controls=116), African Americans (cases=120, controls=124) and Cuban Americans (cases=160, controls=181) of South Florida were explored. Five single nucleotide polymorphisms of gene PPARGC1A were evaluated in each ethnicity for their disease association. In Haitian Americans, rs7656250 (OR= 0.22, pp=0.03) had significant protective association with T2D but had risk association in African Americans for rs7656250 (OR=1.02, p=0.96) and rs4235308 (OR=2.53, p=0.03). We found that in Haitian American females, both rs7656250 (OR=0.23, pp=0.03) had protective association with T2D. In African American females, rs7656250 (OR=1.14, p=0.78) had risk association whereas in males, it had significant protective effect (OR=0.37, p=0.04). However, the risk association exhibited by rs4235308 was stronger in African American females (OR=2.69, p=0.03) than males (OR=1.16, p=0.72). In Cuban Americans, only rs7656250 showed significant risk association with T2D (OR=6.87, p=0.02) which was stronger in females alone (OR=7.67, p=0.01). We also observed significant differences among correlations of PPARGC1A SNPs and T2D phenotypes. Positive correlation was observed for log Hs-CRP with rs3774907 (pp=0.03) in Cuban Americans respectively. Correlation of log A1C with rs7656250 (p=0.02) was positive in Cuban Americans while it was negative for rs3774907 in Haitian Americans (ppPPARGC1A correlations with T2D and its phenotypes among the three ethnicities studied (ii) the associations of PPARGC1A SNPs showed significant effect modification by sex. The findings suggest that variations in effects of PPARGC1A gene polymorphisms among three ethnicities and between sexes may have biomedical implications for the development of T2D as well as the phenotypes related to T2D.