503 resultados para ANCESTRY
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The Lewis blood group system involves two major antigens, Lea and Leb. Their antigenic determinants are not primary gene products but are synthesized by the transfer of sugar subunits to a precursory chain by a specific enzyme which is the product of the FUT3 gene (Lewis gene). The presence of three FUT3 gene single nucleotide polymorphisms (SNPs) (59T > G; 508G > A and 1067T > A) was related to the Lewis phenotype of erythrocytes from 185 individuals of Japanese ancestry living in the town of Tomé-Açu in the Brazilian Amazon region. This relationship was detected using a serological hemagglutination test and the Dot-ELISA assay along with the molecular technique PCR-RFLP. We found that the three SNPs investigated in this study only accounted for a proportion of the Lewis-negative phenotype of the erythrocytes.
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Background: Warfarin-dosing pharmacogenetic algorithms have presented different performances across ethnicities, and the impact in admixed populations is not fully known. Aims: To evaluate the CYP2C9 and VKORC1 polymorphisms and warfarin-predicted metabolic phenotypes according to both self-declared ethnicity and genetic ancestry in a Brazilian general population plus Amerindian groups. Methods: Two hundred twenty-two Amerindians (Tupinikin and Guarani) were enrolled and 1038 individuals from the Brazilian general population who were self-declared as White, Intermediate (Brown, Pardo in Portuguese), or Black. Samples of 274 Brazilian subjects from Sao Paulo were analyzed for genetic ancestry using an Affymetrix 6.0 (R) genotyping platform. The CYP2C9*2 (rs1799853), CYP2C9*3 (rs1057910), and VKORC1 g.-1639G>A (rs9923231) polymorphisms were genotyped in all studied individuals. Results: The allelic frequency for the VKORC1 polymorphism was differently distributed according to self-declared ethnicity: White (50.5%), Intermediate (46.0%), Black (39.3%), Tupinikin (40.1%), and Guarani (37.3%) (p < 0.001), respectively. The frequency of intermediate plus poor metabolizers (IM + PM) was higher in White (28.3%) than in Intermediate (22.7%), Black (20.5%), Tupinikin (12.9%), and Guarani (5.3%), (p < 0.001). For the samples with determined ancestry, subjects carrying the GG genotype for the VKORC1 had higher African ancestry and lower European ancestry (0.14 +/- 0.02 and 0.62 +/- 0.02) than in subjects carrying AA (0.05 +/- 0.01 and 0.73 +/- 0.03) (p = 0.009 and 0.03, respectively). Subjects classified as IM + PM had lower African ancestry (0.08 +/- 0.01) than extensive metabolizers (0.12 +/- 0.01) (p = 0.02). Conclusions: The CYP2C9 and VKORC1 polymorphisms are differently distributed according to self-declared ethnicity or genetic ancestry in the Brazilian general population plus Amerindians. This information is an initial step toward clinical pharmacogenetic implementation, and it could be very useful in strategic planning aiming at an individual therapeutic approach and an adverse drug effect profile prediction in an admixed population.
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The frequency distribution of SNPs and haplotypes in the ABCB1, SLCO1B1 and SLCO1B3 genes varies largely among continental populations. This variation can lead to biases in pharmacogenetic studies conducted in admixed populations such as those from Brazil and other Latin American countries. The aim of this study was to evaluate the influence of self-reported colour, geographical origin and genomic ancestry on distributions of the ABCB1, SLCO1B1 and SLCO1B3 polymorphisms and derived haplotypes in admixed Brazilian populations. A total of 1039 healthy adults from the north, north-east, south-east and south of Brazil were recruited for this investigation. The c.388A>G (rs2306283), c.463C>A (rs11045819) and c.521T>C (rs4149056) SNPs in the SLCO1B1 gene and c.334T>G (rs4149117) and c.699G>A (rs7311358) SNPs in the SLCO1B3 gene were determined by Taqman 5'-nuclease assays. The ABCB1 c.1236C>T (rs1128503), c.2677G>T/A (rs2032582) and c.3435C>T (rs1045642) polymorphisms were genotyped using a previously described single-base extension/termination method. The results showed that genotype and haplotype distributions are highly variable among populations of the same self-reported colour and geographical region. However, genomic ancestry showed that these associations are better explained by a continuous variable. The influence of ancestry on the distribution of alleles and haplotype frequencies was more evident in variants with large differences in allele frequencies between European and African populations. Design and interpretation of pharmacogenetic studies using these transporter genes should include genomic controls to avoid spurious conclusions based on improper matching of study cohorts from Brazilian populations and other highly admixed populations.
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Background: Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. Methods: We explored the applicability of single-tube 34-plex ancestry informative markers (AIM) single nucleotide polymorphisms (SNPs) to estimate the African Component of Ancestry (ACA) to design a future case-control association study of a Brazilian urban sample. Results: One hundred eighty individuals (107 case group; 73 control group) self-described as white, brown-intermediate or black were selected. The proportions of the relative contribution of a variable number of ancestral population components were similar between case and control groups. Moreover, the case and control groups demonstrated similar distributions for ACA <0.25 and >0.50 categories. Notably a high number of outlier values (23 samples) were observed among individuals with ACA <0.25. These individuals presented a high probability of Native American and East Asian ancestral components; however, no individuals originally giving these self-described ancestries were observed in this study. Conclusions: The strategy proposed for the assessment of ancestry and adjustment of case and control groups for an association study is an important step for the proper construction of the study, particularly when subjects are taken from a complex urban population. This can be achieved using a straight forward multiplexed AIM-SNPs assay of highly discriminatory ancestry markers.
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Background: IL28B polymorphisms are predictors of therapy response in hepatitis C virus (HCV) patients. We do not know whether they are markers of treatment response in admixed populations or not. Aims: To determine whether IL28B polymorphisms are predictors of therapy response in patients with HCV from an admixed population and are influenced by genetic ancestry. Methods: rs12979860 and rs8099917 were genotyped in 222 HCV patients treated with pegylated interferon and ribavirin. Ancestry was determined using genetic markers. Results: IL28B rs12979860 C/C was associated with sustained virological response (SVR), whereas C/T and T/T were associated with failure to therapy (P = 1.12 x 10(-5)). IL28B rs8099917 T/T was associated with SVR, and G/G and G/T were associated with nonresponse/ relapse (NR/R) (P = 8.00 x 10(-3)). Among HCV genotype 1 patients with C/C genotype, genomic ancestry did not interfere with therapy response. Among patients with rs12979860 T/T genotype, African genetic contribution was greater in the NR/R group (P = 1.51 x 10(-3)), whereas Amerindian and European genetic ancestry contribution were higher in the SVR group (P = 3.77 x 10(-3) and P = 2.16 x 10(-2) respectively). Among HCV type 1 patients with rs8099917 T/T, African genetic contribution was significantly greater in the NR/R group (P = 5.0 x 10(-3)); Amerindian and European ancestry genetic contribution were greater in the SVR group. Conclusion: IL28B rs12979860 and rs8099917 polymorphisms were predictors of therapy response in HCV genotypes 1, 2 and 3 subjects from an admixed population. Genomic ancestry did not interfere with response to therapy in patients with rs12979860 C/C, whereas it interfered in patients with C/T and T/T genotypes. Among HCV genotype 1 rs8099917 T/T patients, genomic ancestry interfered with response to therapy.
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Invasive studies suggest that healthy children living at high altitude display pulmonary hypertension, but the data to support this assumption are sparse. Nitric oxide (NO) synthesized by the respiratory epithelium regulates pulmonary artery pressure, and its synthesis was reported to be increased in Aymara high-altitude dwellers. We hypothesized that pulmonary artery pressure will be lower in Aymara children than in children of European ancestry at high altitude, and that this will be related to increased respiratory NO. We therefore compared pulmonary artery pressure and exhaled NO (a marker of respiratory epithelial NO synthesis) between large groups of healthy children of Aymara (n = 200; mean +/- SD age, 9.5 +/- 3.6 years) and European ancestry (n = 77) living at high altitude (3,600 to 4,000 m). We also studied a group of European children (n = 29) living at low altitude. The systolic right ventricular to right atrial pressure gradient in the Aymara children was normal, even though significantly higher than the gradient measured in European children at low altitude (22.5 +/- 6.1 mm Hg vs 17.7 +/- 3.1 mm Hg, p < 0.001). In children of European ancestry studied at high altitude, the pressure gradient was 33% higher than in the Aymara children (30.0 +/- 5.3 mm Hg vs 22.5 +/- 6.1 mm Hg, p < 0.0001). In contrast to what was expected, exhaled NO tended to be lower in Aymara children than in European children living at the same altitude (12.4 +/- 8.8 parts per billion [ppb] vs 16.1 +/- 11.1 ppb, p = 0.06) and was not related to pulmonary artery pressure in either group. Aymara children are protected from hypoxic pulmonary hypertension at high altitude. This protection does not appear to be related to increased respiratory NO synthesis.
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CONTEXT Lipoid congenital adrenal hyperplasia (CAH) is the most severe form of CAH leading to impaired production of all adrenal and gonadal steroids. Mutations in the gene encoding steroidogenic acute regulatory protein (StAR) cause lipoid CAH. OBJECTIVE We investigated three unrelated patients of Swiss ancestry who all carried novel mutations in the StAR gene. All three subjects were phenotypic females with absent Müllerian derivatives, 46,XY karyotype, and presented with adrenal failure. METHODS AND RESULTS StAR gene analysis showed that one patient was homozygous and the other two were heterozygous for the novel missense mutation L260P. Of the heterozygote patients, one carried the novel missense mutation L157P and one had a novel frameshift mutation (629-630delCT) on the second allele. The functional ability of all three StAR mutations to promote pregnenolone production was severely attenuated in COS-1 cells transfected with the cholesterol side-chain cleavage system and mutant vs. wild-type StAR expression vectors. CONCLUSIONS These cases highlight the importance of StAR-dependent steroidogenesis during fetal development and early infancy; expand the geographic distribution of this condition; and finally establish a new, prevalent StAR mutation (L260P) for the Swiss population.
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The northern region of the Indian subcontinent is a vast landscape interlaced by diverse ecologies, e.g. the Gangetic plain and the Himalayas. A great number of ethnic groups are found there, displayed as a multitude of languages and cultures. The Tharu represent one of the largest and linguistically most diversified such groups, scattered across the Tarai region of Nepal and bordering Indian states. Their origins are uncertain. Hypotheses have been advanced about an Austroasiatic affinity, Tibeto-Burman origins, as well as aboriginal roots in the Tarai. Several Tharu groups speak a variety of Indo-Aryan languages, but have traditionally been described by ethnographers as representing an East Asian phenotype. Their ancestry and intra-population diversity had previously been tested only for haploid (mtDNA and Y-chromosome) markers in a small portion of the population. This study presents the first systematic genetic survey of the Tharu from both Nepal and the Indian states of Uttaranchal and Uttar Pradesh, using genome-wide SNPs and haploid (mtDNA and Y-chromosome) markers. The results suggest that the 'ethnic' construct of Tharu is likely to have lain in the Tarai region, with a reconstructible radiation to Uttaranchal and Uttar Pradesh. Despite extensive admixture with other local communities, Tharu sub-populations preserve strong genetic signatures that indicate a common ancestry.
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BACKGROUND Vitamin D deficiency is prevalent in HIV-infected individuals and vitamin D supplementation is proposed according to standard care. This study aimed at characterizing the kinetics of 25(OH)D in a cohort of HIV-infected individuals of European ancestry to better define the influence of genetic and non-genetic factors on 25(OH)D levels. These data were used for the optimization of vitamin D supplementation in order to reach therapeutic targets. METHODS 1,397 25(OH)D plasma levels and relevant clinical information were collected in 664 participants during medical routine follow up visits. They were genotyped for 7 SNPs in 4 genes known to be associated with 25(OH)D levels. 25(OH)D concentrations were analyzed using a population pharmacokinetic approach. The percentage of individuals with 25(OH)D concentrations within the recommended range of 20-40ng/ml during 12 months of follow up and several dosage regimens were evaluated by simulation. RESULTS A one-compartment model with linear absorption and elimination was used to describe 25(OH)D pharmacokinetics, while integrating endogenous baseline plasma concentrations. Covariate analyses confirmed the effect of seasonality, body mass index, smoking habits, the analytical method, darunavir/r and the genetic variant in GC (rs2282679) on 25(OH)D concentrations. 11% of the interindividual variability in 25(OH)D levels was explained by seasonality and other non-genetic covariates and 1% by genetics. The optimal supplementation for severe vitamin D deficient patients was 300000 IU two times per year. CONCLUSIONS This analysis allowed identifying factors associated with 25(OH)D plasma levels in HIV-infected individuals. Improvement of dosage regimen and timing of vitamin D supplementation is proposed based on those results.
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The Tibeto-Burman linguistic phylum was identified in 1823. However, the term “Tibeto-Burman” was later used with two different mean- ings, one by scholars following Klaproth’s polyphyletic framework and another by scholars operating within the Indo-Chinese paradigm. Yet the enduring failure of Sino-Tibetanists to produce any evidence for the Indo-Chinese phylogenetic model compels us to conclude that there is no such language family as Sino-Tibetan. Instead, Tibetan forms part of the Trans-Himalayan linguistic phylum, or Tibeto-Burman in Klaproth’s sense. Robert Shafer coined the terms “Bodic” and “Bodish” for subgroups including Tibetan and languages with varying degrees of linguistic propin- quity to Tibetan, and Nicolas Tournadre has also recently coined the term “Tibetic.” What are Tibetic, Bodish, and Bodic? Which languages are the closest relatives of Tibetan? What do we know about the structure of the Trans-Himalayan linguistic phylum as a whole? Based on the phylogeny of the language family, which inferences can be made about the ethnolinguis- tic prehistory of the Tibetan Plateau and surrounding regions?
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Bernhard Wachstein
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Bernhard Wachstein
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The sunflower alliance of families comprises nearly 10% of all flowering plant species and includes the largest of all plant families, the sunflower family Asteraceae, which has 23,000 species, and the bellflower family Campanulaceae. Both are worldwide in distribution, but the majority of their species occur in the northern hemisphere. Recently it has been shown that a number of small, woody families from the Australian–Southwest Pacific area also belong in this relationship. Here we add yet another such family and present phylogenetic, biogeographic, and chronological analyses elucidating the origin of this large group of plants. We show that the ancestral lineages are confined to Malesia, Australia, New Guinea, and New Zealand and that the sunflower and bellflower families represent phylogenetically derived lineages within a larger group with a Cretaceous and southern-hemisphere, presumably East Gondwana, ancestry. Their highly derived position in the flowering plant phylogeny makes this significant for understanding the evolution of flowering plants in general.