ABSTRACT
The hepatic lipase plays a central role in the lipid metabolism, catalyzing the hydrolysis of phospholipids, monoglycerides, diglycerides, and triglycerides, and acyl-CoA. It is also implied in the conversion of very low-density lipoprotein and intermediate density lipoprotein to low density lipoproteins. As a consequence, the gene encoding the hepatic lipase (LIPC) is associated with several diseases derived from the imbalance of lipids that are in general derived from the interaction between life styles and genetic architecture. Therefore, it is interesting to understand more about the characteristics of the microevolutionary processes affecting genes that, like LIPC, have a role in nutrition and lipid metabolism in human populations. We explored the selection signatures on LIPC in 26 populations, detecting three regions under recent positive selection
ABSTRACT
Background: Alleles involved in inefficient (ADH1B2*2 and ALDH2*2) or efficient (SNP6, ADH4 gene) alcohol metabolism may influence the risk of alcoholism. Alcoholism susceptibility has been classified as protector and risk-dependence phenotypes, associated with inefficient and efficient alcohol genetic metabolizing variants, respectively. Aim: To investigate the possible association between genetic protective and risk-dependence variants and alcohol intake patterns. Material and Methods: Saliva DNA samples were obtained and the AUDIT (Alcohol Use Disorders Identification Test) questionnaire was applied to 210 university students aged between 18 and 25 years old. Results: No statistically significant association between protective or risk-dependence genetic variants and alcohol pattern intake was detected. However, new categories of alcohol intake patterns-not included in the AUDIT questionnaire-were identified. Conclusions: No association between the protector and risk-dependence phenotypes and patterns of alcohol consumption was detected in this sample of students.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Young Adult , Alcohol Drinking/genetics , Phenotype , Polymorphism, Single Nucleotide , Alcohol Drinking/metabolism , Chile , Genetic Predisposition to Disease , Students , UniversitiesABSTRACT
We examined 103 nucleotide sequences of the HIV-1 env gene, sampled from 35 countries and tested: I) the random (neutral) distribution of the number of nucleotide changes; II) the proportion of bases at molecular equilibrium; III) the neutral expected homogeneity of the distribution of new fxated bases; IV) the hypothesis of the neighbor infuence on the mutation rates in a site. The expected random number of fxations per site was estimated by Bose-Einstein statistics, and the expected frequencies of bases by matrices of mutation-fxation rates. The homogeneity of new fxations was analyzed using χ2 and trinomial tests for homogeneity. Fixations of the central base in trinucleotides were used to test the neighbor infuence on base substitutions. Neither the number of fxations nor the frequencies of bases ftted the expected neutral distribution. There was a highly signifcant heterogeneity in the distribution of new fxations, and several sites showed more transversions than transitions, showing that each nucleotide site has its own pattern of change. These three independent results make the neutral theory, the nearly neutral and the neighbor infuence hypotheses untenable and indicate that evolution of env is rather highly selective.