A straightforward multiallelic significance test for the Hardy-Weinberg equilibrium law

Much forensic inference based upon DNA evidence is made assuming Hardy-Weinberg Equilibrium (HWE) for the genetic loci being used. Several statistical tests to detect and measure deviation from HWE have been devised, and their limitations become more obvious when testing for deviation within multiallelic DNA loci. The most popular methods-Chi-square and Likelihood-ratio tests-are based on asymptotic results and cannot guarantee a good performance in the presence of low frequency genotypes. Since the parameter space dimension increases at a quadratic rate on the number of alleles, some authors suggest applying sequential methods, where the multiallelic case is reformulated as a sequence of “biallelic” tests. However, in this approach it is not obvious how to assess the general evidence of the original hypothesis; nor is it clear how to establish the significance level for its acceptance/rejection. In this work, we introduce a straightforward method for the multiallelic HWE test, which overcomes the aforementioned issues of sequential methods. The core theory for the proposed method is given by the Full Bayesian Significance Test (FBST), an intuitive Bayesian approach which does not assign positive probabilities to zero measure sets when testing sharp hypotheses. We compare FBST performance to Chi-square, Likelihood-ratio and Markov chain tests, in three numerical experiments. The results suggest that FBST is a robust and high performance method for the HWE test, even in the presence of several alleles and small sample sizes

Consumo de carnes por adolescentes do Sul do Brasil

Objetivo: Descrever a frequência de consumo de diferentes tipos de carnes conforme variáveis sociodemográficas e nutricionais, e analisar o consumo, em adolescentes do Sul do Brasil, de dieta rica em gordura conforme os tipos de carne consumidos. Métodos: Estudo transversal realizado com adolescentes pertencentes à coorte de nascimentos de 1993, em Pelotas (RS). A frequência de consumo de carnes vermelhas, brancas, vísceras e embutidos foi avaliada por um Questionário de Frequência de Consumo Alimentar, adaptado para este estudo. A ingestão de dieta rica em gordura foi avaliada a partir do instrumento proposto por Block. As variáveis independentes foram sexo, cor da pele, nível socioeconômico, escolaridade materna e estado nutricional. Nas análises estatísticas, foram utilizados testes Qui-quadrado de heterogeneidade e de tendência linear. Resultados: Foram avaliados 4.325 adolescentes com idade média de 14,7, DP=0,3 anos, dos quais 51,2% eram do sexo feminino. A frequência de consumo diário de carnes vermelhas foi maior do que a de carnes brancas (43,0%e 9,7%, respectivamente). O consumo de embutidos por mais do que quatro vezes por semana foi referido por 48,5% dos indivíduos, e 81,4% relataram consumir vísceras raramente ou nunca. Adolescentes de maior nível socioeconômico e filhos de mães com maior escolaridade apresentaram maior consumo de carnes vermelhas e embutidos, enquanto aqueles em situação oposta apresentaram maior consumo de carnes brancas. Adolescentes que consomem carnes com maior frequência também consomem dieta rica em gordura. Conclusão: As carnes consumidas com maior frequência pelos adolescentes foram as vermelhas e os embutidos. No entanto, adolescentes de maior nível socioeconômico consomem carnes vermelhas com maior frequência, enquanto adolescentes menos favorecidos economicamente consomem mais carnes brancas.Objective: The present study investigated the consumption frequency of various meats according to sociodemographic and nutritional variables and analyzed the consumption of high-fat diets according to type of meat by southern Brazilian adolescents. Methods: This cross-sectional study included the 1993 birth cohort from Pelotas (RS). The consumption frequency of red, white and organ meats and sausage were investigated by a food frequency questionnaire adapted for this study. Dietary fat content was determined as proposed by Block. The independent variables were gender, skin color, socioeconomic level, maternal education level and nutritional status. The statistical analyses included the Chi-square linear tendency test and the Chi-square test of homogeneity. Results: A total of 4,325 adolescents with a mean age of 14.7 years, SD=0.3 years, were assessed, of which 51.2% were females. Red meat was consumed more frequently daily than white meat (43.0% and 9.7%, respectively). Sausage consumption frequency greater than 4 times per week was reported by 48.5% of the sample, and 81.4% reported to consume organ meats rarely or never. Adolescents of higher socioeconomic levels and of mothers with higher education levels consumed more red meats and sausages, while those in the opposite situation consumed more white meats. Adolescents who consumed meats more frequently also consumed a high-fat diet. Conclusion: Red meats and sausages were the meats most frequently consumed by the study adolescents. However, adolescents of higher socioeconomic levels consumed red meats more often, while those of lower socioeconomic levels consumed white meats more often