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The current Chilean population originated from admixture between aboriginal populations (Amerindians) and Spanish conquerors of European origin. Consequently, the unions that gave rise to the Chilean population were chiefly between Spanish males and aboriginal females, and not the converse. To test the hypothesis that the Y chromosome of the Chilean population is mainly of Spanish origin, while the other chromosomes are from mixed (European and aboriginal) origin, we studied the DYS19 and DYS199 loci in two samples. One sample was obtained from a high socioeconomic stratum, while a second sample was from a low stratum. We studied male blood donors (N = 187) from Santiago, the capital of the country. Subjects were typed for the autosomal ABO and Rh (locus D) blood groups, and for the Y-linked DYS19 and the DYS199 loci, reported as Y-chromosome haplotypes. The aboriginal admixture was estimated for each genetic marker. The percentage of aboriginal admixture was 38.17% for the ABO system and 31.28% for the Rh system in the low socioeconomic stratum and 19.22% and 22.5%, respectively, in the high stratum. Y-chromosome haplotype frequencies constructed from the DYS19 and DYS199 loci demonstrated that the main haplotypes were DYS19*14/DYS199 C, as is often the case with many European populations, and DYS19*13/DYS199 C. The aboriginal admixture from Y-haplotype frequencies was estimated to be 15.83% in the low socioeconomic stratum and 6.91% in the high stratum. These values are lower than the values found using autosomal genetic markers, and are consistent with the historical background of the population studied. This study highlights the population genetic consequences of the asymmetric pattern of genome admixture between two ancestral populations (European and Amerindian).

The average exclusion probability is a measure of efficiency in paternity testing; it refers to the a priori ability of a battery of tests to detect paternity inconsistencies. This parameter measures the capacity of the system to detect a false accusation of paternity. Traditionally, this average exclusion probability has been estimated as the probability of excluding a man who is not the father by an inconsistency in at least one of the studied loci. We suggest that this criterion should be corrected, as currently the presumed father is excluded when at least three genetic inconsistencies are found with the child being tested, not just one. This change of criterion has occurred because of the use of microsatellite loci, whose mutation rates are much greater than those of the coding genes used previously in paternity studies. We propose the use of the average probability of exclusion for at least three loci (not only one), as an honest measure of the combined probability of exclusion of several loci, and we propose an algebraic expression to calculate it.

Background: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socioeconomic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. Results: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors.

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Objective Provide a timely, rigorous and continuously updated summary of the evidence on the role of remdesivir in the treatment of patients with COVID-19. Methods Eligible studies were randomized trials evaluating the effect of remdesivir versus placebo or no treatment. We conducted searches in the special L·OVE (Living OVerview of Evidence) platform for COVID-19, a system that performs regular searches in databases, trial registries, preprint servers and websites relevant to COVID-19. All the searches covered the period until 25 August 2020. No date or language restrictions were applied. Two reviewers independently evaluated potentially eligible studies according to predefined selection criteria, and extracted data on study characteristics, methods, outcomes, and risk of bias, using a predesigned, standardized form. We performed meta-analyses using random-effect models and assessed overall certainty in evidence using the GRADE approach. A living, web-based version of this review will be openly available during the COVID-19 pandemic. Results Our search strategy yielded 574 references. Finally, we included threerandomized trials evaluating remdesivir in addition to standard care versus standard care alone. The evidence is very uncertain about the effect of remdesivir on mortality (RR 0.7, 95% CI 0.46 to 1.05; very low certainty evidence) and the need for invasive mechanical ventilation (RR 0.69, 95% CI 0.39 to 1.24; very low certainty evidence). On the other hand, remdesivir likely results in a large increase in the incidence of adverse effects in patients with COVID-19 (RR 1.29, 95% CI 0.58 to 2.84; moderate certainty evidence). Conclusions The evidence is insufficient for the outcomes critical for making decisions on the role of remdesivir in the treatment of patients with COVID-19, so it is impossible to balance potential benefits, if there are any, with the adverse effects and costs. PROSPERO Registration number: CRD42020183384.

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