A total of 1037 individuals living in five different sociogeographic regions of Brazil were studied in relation to 12 short tandem repeat polymorphisms. The objective was to assess the degree of European, African, and Amerindian contributions to their gene pools. Although most of the genetic variability was found within regions, significant differences were also observed between regions. The estimated relative proportions of the above-indicated continental contributions showed intermediate values between those obtained with uniparental (mtDNA, Y-chromosome) data, and a higher percentage of European heritage as compared to previous autosome results. A north-south trend of increasing European contribution was also found, in agreement with the history of the Brazilian population.

COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children’s non-specific immune profile is dominated by naive lymphocytes and HLA-DRhighCX3CR1low dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8+TNF+ T cells responses to S peptide pool but stronger responses to N and M peptide pools. Finally, viral mRNA is more abundant in pediatric patients. Our data thus support a scenario in which SARS-CoV-2 infected children contribute to transmission yet are less susceptible to COVID-19 symptoms due to strong and differential responses to the virus.

The effect of colchicine on the protocorm-like bodies of Cattleya intermedia L. (Orchidaceae) cultured in vitro was studied. Different concentrations of the drug (0.00, 0.05, 0.10 and 0.20%) as well as two times of culture (4 or 8 days) were tested to determine the best treatment for the induction of tetraploid plants. Of the 3 colchicine levels applied, 0.05 and 0.10% of drug treatments appeared to be effective on the production of mixoploids and tetraploids and could be further used in breeding programs. The suitability of stomatal area and stomata density as criteria for the distinction between diploids and tetraploids was also tested. The results suggested that tetraploid plants could be identified with a fair amount of certainty when the screening was based on the density of stomata.

The CB1 cannabinoid receptor and its endogenous ligands, the endocannabinoids, are involved in energy balance control, stimulating appetite and increasing body weight in wasting syndromes. Different studies have investigated the relationship between polymorphisms of the cannabinoid receptor 1 (CNR1) gene and obesity with conflicting results. In the present study, we investigated the 1359G/A (rs1049353), 3813A/G (rs12720071) and 4895A/G (rs806368) polymorphisms in the CNR1 gene in a Brazilian population of European descent. To verify the association between these variants and obesity-related traits in this population, 756 individuals were genotyped by PCR-RFLP methods. The 4895G allele was associated with waist to hip ratio (WHR) (P = 0.014; P = 0.042 after Bonferroni correction). An additive effect with the GAA haplotype was associated with WHR (P = 0.028), although this statistical significance disappeared after Bonferroni correction (P = 0.084). No significant association was observed between the genotypes of the 1359G/A and 3813A/G polymorphisms and any of the quantitative variables investigated. Our findings suggest that CNR1 gene polymorphism is associated with central obesity in this Brazilian population of European ancestry.

A total of 2,708 individuals from the European-derived population of Rio Grande do Sul, divided into seven mesoregions, and of 226 individuals of similar origin from Santa Catarina were studied. Seventeen protein genetic systems, as well as grandparents' nationalities, individuals' surnames, and interethnic admixture were investigated. The alleles which presented the highest and lowest differences were GLO1*2 (16%) and PGD*A (2%), respectively, but in general no significant genetic differences were found among mesoregions. The values observed were generally those expected for individuals of European descent, with the largest difference being a lower prevalence (34-39%) of P*1. Significant heterogeneity among mesoregions was observed for the other variables considered, and was consistent with historical records. The Amerindian contribution to the gene pool of European-derived subjects in Rio Grande do Sul was estimated to be as high as 11%. Based on the four data sets, the most general finding was a tendency for a northeast-southwest separation of the populations studied. Seven significant phenotype associations between systems were observed at the 5% level (three at the 0.1% level). Of the latter, the two most interesting (since they were also observed in other studies) were MNSs/Duffy and Rh/ACP.

A total of 337 Kaingang and Guarani Indians from two localities were studied in relation to 18 protein genetic loci. In one of the localities, members of these two groups live side by side but show little genetic similarity, emphasizing the influence of cultural factors in the mating behavior of human groups. Integrating the present results with previous ones, it was verified that the genetic relationships among six Kaingang populations do not follow the pattern expected from their geographical distribution. Comparisons made with three other Ge˜‐speaking tribes indicate that the Kaingang did not separate well from them. Most (96%) of the variability in the six polymorphic systems considered occur at the intrapopulational level. Am. J. Hum. Biol. 9:505–512, 1997. © 1997 Wiley‐Liss, Inc.

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