ABSTRACT. Due to the miscegenation of the Brazilian population, the central region of Brazil was colonized by internal migration of individuals from different origins, who contributed to the genetic diversity existing in this population. The purpose of this study was to estimate population parameters based on the allele frequencies for 15 polymorphic autosomal short-tandem repeat (STR) loci present in the population of the State of Goiás in the central region of Brazil, and to compare the results with those of others from different Brazilian populations. DNA was obtained from a sample of 986 unrelated individuals by a commercial reagent kit and was quantified by spectrometry for later amplification in the thermocycler. These loci, commonly used in forensics and paternity testing, reflected Hardy-Weinberg equilibrium in this population. The D18S51 and Penta E loci had the highest number of alleles, while the observed heterozygosity reached the highest rates in FGA (0.920), D7S820 (0.870), and vWA (0.867) markers. Genetic diversity reached the highest levels in Penta E (0.906), Penta D (0.873), and D18S51 (0.860) markers, and the investigated forensic parameters showed high average values, with 93% power of discrimination, polymorphism information content of 78%, gene diversity of 79%, and observed heterozygosity of 79%. Similar to the other populations of Brazil, the population of the Midwest is derived from the admixture of 3 main parental groups: Amerindian, European, particularly Portuguese, and Africans from sub-Saharan Africa. In this context, the overall distribution of allele frequencies in the STR markers of various Brazilian populations is quite similar to the data obtained in this study.

The appearance of new mutations in polymorphic markers plays a central role in a range of genetic applications, including dating phylogenetic events, informing disease studies, and evaluating forensic evidence. The present study estimated the mutation rates of 21 autosomal STR loci in a population from Central Brazil. We studied 15 046 paternity cases from Goiás, Brazil from August 2012 to February 2015. We identified 262 mutations in the 21 loci. The loci that presented more mutations were FGA and D18S51, with a total of 46 and 28 mutations, respectively. The results showed mutational rates ranging from 1.7 × 10 to 7.6 × 10 mutations per site/region and the overall mutational rate was 2.1 × 10 ; these values were within the expected values for the STR markers. The most common type of mutation was one-step mutation, which totaled 96.2%. We found a higher rate of mutations of paternal origin (67.6%) than of mutations of maternal origin. The occurrence of mutations in STRs has important consequences for human identification, including the definition of criteria for exclusion in paternity testing and interpretation of genetic profiles in criminal cases.

Evaluation of polymorphisms in repair and detoxification genes in alcohol drinkers and non-drinkers using capillary electrophoresisAlcohol use disorder (AUD) causes about 3.3 million deaths around the world each year. It is the primary risk factor for the global burden of diseases in American countries. Longterm abuse of alcohol induces numerous molecular and biochemical changes in tissues exposed to alcohol. The toxic effects of alcohol are mediated by DNA damage through various mechanisms, such as induction of oxidative damage, DNA adducts, crosslinks, and DNA strand breaks. The main aim of the current study was to compare the frequency of SNP polymorphisms in XRCC1 (rs7997782) and GSTP1 (rs1695) genes involved in DNA repair of single strand breaks (SSB) and xenobiotic detoxification between alcohol addicts and a control group comprised of non-drinkers. Genetic polymorphisms were identified following allelic specific PCR designed to generate the amplicons containing the variants. Then amplicons were sequenced, and sequences were aligned against the human genome reference deposited in GenBank using the CLC Sequence Viewer software (version 7.6.1). The GG homozygotes in rs1695 (GSTP1) were significantly (p = 0.023) 3.8x more frequent among those with AUD when compared to the control group. No SNP variation was observed in rs7997782 (XRCC1). rs1695 variant has been associated with susceptibility to various diseases, including those related to alcohol consumption.