962 resultados para allele polymorphism


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The objective of this work was to evaluate the effects of single-nucleotide polymorphisms (SNPs) in the genes IGF1 (AF_017143.1:g.198C>T), MSTN (AF_320998.1:g.433C>A), MYOD1 (NC_007313:g.1274A>G) and MYF5 (NC_007303:g.1911A>G) on carcass and meat traits in Nelore (Bos indicus) and Nelore x B. taurus. A total of 300 animals were genotyped and phenotyped for rib eye area (REA), backfat thickness (BT), intramuscular fat (IF), shear force (SF) and myofibrillar fragmentation index (MFI). The effects of allele substitution for each SNP were estimated by regression of the evaluated phenotypes on the number of copies of a particular allele using the general linear model. The polymorphism at IGF1 was non-informative in Nelore animals. In crossbred animals, the IGF1 C allele was associated with greater REA. However, this relation was not significant after Bonferroni correction for multiple testing. The A allele of the MSTN polymorphism was absent in Nelore cattle and was only found in two crossbred animals. The polymorphisms of MYOD1 and MYF5 were little informative in Nelore animals with G allele frequency of 0.097 and A allele frequency of 0.031, respectively. These markers show no association with the analyzed traits in the total sample of evaluated animals.

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The aim of the present study, involving 463 women of reproductive age, was to evaluate for the first time the relationship between endometriosis, endometriosis-related infertility, and a recently described functional polymorphism in the ALOX15 gene, reported to be essential for implantation. In our study population, ALOX15 -292 C/T was not correlated either with the risk of developing an endometriosis or with the risk of infertility.

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The cytosine deaminase APOBEC3G, in the absence of the human immunodeficiency virus type 1 (HIV-1) accessory gene HIV-1 viral infectivity factor (vif), inhibits viral replication by introducing G-->A hypermutation in the newly synthesized HIV-1 DNA negative strand. We tested the hypothesis that genetic variants of APOBEC3G may modify HIV-1 transmission and disease progression. Single nucleotide polymorphisms were identified in the promoter region (three), introns (two), and exons (two). Genotypes were determined for 3,073 study participants enrolled in six HIV-AIDS prospective cohorts. One codon-changing variant, H186R in exon 4, was polymorphic in African Americans (AA) (f = 37%) and rare in European Americans (f < 3%) or Europeans (f = 5%). For AA, the variant allele 186R was strongly associated with decline in CD4 T cells (CD4 slope on square root scale: -1.86, P = 0.009), The 186R allele was also associated with accelerated progression to AIDS-defining conditions in AA. The in vitro antiviral activity of the 186R enzyme was not inferior to that of the common H186 variant. These studies suggest that there may be a modifying role of variants of APOBEC3G on HIV-1 disease progression that warrants further investigation.

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Nest and territory defence are risky and potentially dangerous behaviours. If the resolution of life history trade-offs differs between individuals, the level of defence may also vary among individuals. Because melanin-based colour traits can be associated with life history strategies, differently coloured individuals may display different nest and territory defence strategies. We investigated this issue in the colour polymorphic tawny owl (Strix aluco) for which plumage varies from dark to light reddish melanic. Accordingly, we found that (1) our presence induced a greater response (flying around) from dark-coloured than light-coloured females and (2) dark reddish males suffered lower nest predation rates than light-coloured males. In experimentally enlarged broods, the probability that females reacted after we played back the hoot calls of a stranger male was higher if these females were lighter reddish; the opposite pattern was found in experimentally reduced broods with dark parents being more reactive than light parents. Finally, darker females alarmed more frequently when paired with a light than with a dark male, suggesting that partners adjust their behaviour to each other. We also tested whether colouration is used as a signal by conspecifics to adjust the level of their defensive behaviour. Accordingly, breeding females responded more vigorously to a dark than a light reddish stuffed tawny owl placed beside their nest. We conclude that melanin-based colouration is a signal of alternative nest and territory defence behaviour that depends on ecological factors.

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Scand J Clin Lab Invest. 2007 Aug 1;:1-11 [Epub ahead of print]

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Homozygous (delta ccr5/delta ccr5) and heterozygous (CCR5/delta ccr5) deletions in the beta-chemokine receptor 5 (CCR5) gene, which encodes for the major co-receptor for macrophage-tropic HIV-1 entry, have been implicated in resistance to HIV infection and in protection against disease progression, respectively. The CCR5/delta ccr5 genotype was found more frequently in long-term nonprogressors (LTNP) (31.0%) than in progressors (10.6%, p < 0.0001), in agreement with previous studies. Kaplan-Meier survival analyses showed that a slower progression of disease, i.e. higher proportion of subjects with CD4+ T cell counts > 500/microl (p = 0.0006) and a trend toward a slower progression to AIDS (p = 0.077), was associated with the CCR5/delta ccr5 genotype. However, when LTNP were analyzed separately, no significant differences in CD4+ T cell counts (p = 0.12) and viremia levels (p = 0.65) were observed between the wild-type (69% of LTNP) and the heterozygous (31.0%) genotypes. Therefore, there are other factors which play a major role in determining the status of nonprogression in the majority of LTNP. Furthermore, there was no evidence that the CCR5/delta ccr5 genotype was associated with different rates of disease progression in the group of progressors. Taken together, these results indicate that the CCR5/delta ccr5 genotype is neither essential nor sufficient for protection against the progression of HIV disease.

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Abstract: The objective of this work was to estimate allelic frequencies of the polymorphisms IGF2/MboII (G > T) of the insulin-like growth factor 2 (IGF2) gene, DQ499531.1:g.134A > T of the pro-melanin-concentrating hormone (PMCH) gene, and DQ667048.1:g.3290G > T of the RARrelated orphan receptor C (RORC) gene in beef cattle of different genetic groups, and to evaluate the associations between these polymorphisms and traits related to carcass composition and meat quality. Data on carcass and meat quality of 499 animals was used: of 313 Nellore (Bos indicus) and of 186 Nellore crossed with different taurine (Bos taurus) breeds. For the IGF2/MboII polymorphism, the frequencies found for the G allele were 0.231 and 0.631 for Nellore and crossed breeds, respectively. For the DQ499531.1:g.134A > T polymorphism, the allelic frequencies of A were 0.850 for Nellore and 0.905 for crossed breeds. For the DQ667048.1:g.3290G > T polymorphism, the allelic frequencies of G were 0.797 and 0.460 for Nellore and crossed breeds, respectively. The evaluated single nucleotide polymorphisms (SNPs) are not significantly associated with carcass and meat traits (rib eye area, back fat thickness, shear force, total lipids, and myofibrillar fragmentation index), suggesting little utility of the analyzed polymorphisms of the IGF2, PMHC, and RORC genes as selection markers in the studied cattle populations.

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FTO is the strongest known genetic susceptibility locus for obesity. Experimental studies in animals suggest the potential roles of FTO in regulating food intake. The interactive relation among FTO variants, dietary intake and body mass index (BMI) is complex and results from previous often small-scale studies in humans are highly inconsistent. We performed large-scale analyses based on data from 177,330 adults (154 439 Whites, 5776 African Americans and 17 115 Asians) from 40 studies to examine: (i) the association between the FTO-rs9939609 variant (or a proxy single-nucleotide polymorphism) and total energy and macronutrient intake and (ii) the interaction between the FTO variant and dietary intake on BMI. The minor allele (A-allele) of the FTO-rs9939609 variant was associated with higher BMI in Whites (effect per allele = 0.34 [0.31, 0.37] kg/m(2), P = 1.9 × 10(-105)), and all participants (0.30 [0.30, 0.35] kg/m(2), P = 3.6 × 10(-107)). The BMI-increasing allele of the FTO variant showed a significant association with higher dietary protein intake (effect per allele = 0.08 [0.06, 0.10] %, P = 2.4 × 10(-16)), and relative weak associations with lower total energy intake (-6.4 [-10.1, -2.6] kcal/day, P = 0.001) and lower dietary carbohydrate intake (-0.07 [-0.11, -0.02] %, P = 0.004). The associations with protein (P = 7.5 × 10(-9)) and total energy (P = 0.002) were attenuated but remained significant after adjustment for BMI. We did not find significant interactions between the FTO variant and dietary intake of total energy, protein, carbohydrate or fat on BMI. Our findings suggest a positive association between the BMI-increasing allele of FTO variant and higher dietary protein intake and offer insight into potential link between FTO, dietary protein intake and adiposity.

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Orosomucoid (ORM) phenotyping has been performed on 329 unrelated Swiss subjects, using immobilized pH gradients with 8 M urea and 2% v/v 2-mercaptoethanol followed by immunoblotting. After desialylation the band patterns of ORM confirmed that the polymorphism of the structural locus ORM1 is controlled by three codominant autosomal alleles (ORM1*F1, ORM1*S and ORM1*F2). One rare and one new allele were detected. The rare variant, tentatively assigned to the second structural locus ORM2, is observed in a cathodal position and named ORM2 B1. The new variant, tentatively assigned to the first structural locus ORM1, is observed in a region located between ORM1 S and ORM1 F2, and named ORM1 F3. Moreover, the pI values of the ORM variants have been measured accurately with Immobiline Dry Plates (LKB): they were found to be within the pH range 4.93-5.14.

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Previously, a single nucleotide polymorphism (SNP), rs9939609, in the FTO gene showed a much stronger association with all-cause mortality than expected from its association with body mass index (BMI), body fat mass index (FMI) and waist circumference (WC). This finding implies that the SNP has strong pleiotropic effects on adiposity and adiposity-independent pathological pathways that leads to increased mortality. To investigate this further, we conducted a meta-analysis of similar data from 34 longitudinal studies including 169,551 adult Caucasians among whom 27,100 died during follow-up. Linear regression showed that the minor allele of the FTO SNP was associated with greater BMI (n = 169,551; 0.32 kg m(-2) ; 95% CI 0.28-0.32, P < 1 × 10(-32) ), WC (n = 152,631; 0.76 cm; 0.68-0.84, P < 1 × 10(-32) ) and FMI (n = 48,192; 0.17 kg m(-2) ; 0.13-0.22, P = 1.0 × 10(-13) ). Cox proportional hazard regression analyses for mortality showed that the hazards ratio (HR) for the minor allele of the FTO SNPs was 1.02 (1.00-1.04, P = 0.097), but the apparent excess risk was eliminated after adjustment for BMI and WC (HR: 1.00; 0.98-1.03, P = 0.662) and for FMI (HR: 1.00; 0.96-1.04, P = 0.932). In conclusion, this study does not support that the FTO SNP is associated with all-cause mortality independently of the adiposity phenotypes.

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DnaSP, DNA Sequence Polymorphism, is a software package for the analysis of nucleotide polymorphism from aligned DNA sequence data. DnaSP can estimate several measures of DNA sequence variation within and between populations (in noncoding, synonymous or nonsynonymous sites, or in various sorts of codon positions), as well as linkage disequilibrium, recombination, gene flow and gene conversion parameters. DnaSP can also carry out several tests of neutrality: Hudson, Kreitman and Aguadé (1987), Tajima (1989), McDonald and Kreitman (1991), Fu and Li (1993), and Fu (1997) tests. Additionally, DnaSP can estimate the confidence intervals of some test-statistics by the coalescent. The results of the analyses are displayed on tabular and graphic form.

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Source/Description: pKM.19 is a 1.0 kb EcoRI genomic fragment in pUC13 (ref. 1,2). pPl was isolated independently but contains the same fragment as pKM.19 (ref. 3)...