Genomic selection in soybean: accuracy and time gain in relation to phenotypic selection

Genomic selection (GS) can potentially accelerate genetic improvement of soybean [Glycine max L. (Merrill)] by reducing the time to complete breeding cycles. The objectives of this study were to (1) explore the accuracy of GS in soybean, (2) evaluate the contribution of intrapopulational structure to the accuracy of GS, and (3) compare the efficiencies of phenotypic selection and GS in soybean. For this, phenotypic and genotypic data were collected from 324 soybean genotypes (243 recombinant inbred lines and 81 cultivars) and GS was performed for five yield related traits. BayesB methodology with a 10-fold cross-validation was used to compute accuracies. The GS accuracies were evaluated for grain yield, plant height, insertion of first pod, days to maturity, and 1000-grain weight at eight locations. We found that GS can reduce the time required to complete a selection cycle in soybean, which can lead to increased production of this commercially important crop. Furthermore, genotypic accuracy was similar regardless of population structure correction.     

Polymorphism rs7895833 in the SIRT1 gene and its association with dyslipidaemia in the elderly

ObjectivesSirtuin 1 is a human protein involved in gene silencing and in inducing the deacetylation of proteins involved in the metabolic and adaptive response mechanisms. Polymorphisms in the SIRT1 gene have been studied with respect to aging. This study aims to determine the allelic and genotypic frequencies of the rs7895833 A/G polymorphism in the SIRT1 gene, and to identify the association between this polymorphism and the co-morbidities prevalent in the elderly population.Material and methodsA total of 216 patients were evaluated in an outpatient clinic in Central Brazil. The individuals underwent validated tests for cognitive impairment and falls risk, serum biochemistry analysis, as well as polymer chain reaction (PCR) with confronting two-pair primers for polymorphism genotyping.Resultsrs7895833 polymorphism in SIRT1 gene was observed in these patients as follows: AA (56/216), AG (138/216), and GG (22/216). The frequency of allele A was 0.58, and that of allele G was 0.42. In the multivariate analysis of the exploratory variables, glucose, high density lipoprotein (HDL) cholesterol, systemic arterial hypertension, dyslipidaemia, and depression, which were associated in the univariate analysis with the polymorphism rs7895833, only dyslipidaemia showed a statistically significant difference in a greater number of individuals with this polymorphism.ConclusionThe variant allele G of the SIRT1 gene polymorphism was found in 42% of these Brazilian geriatric patients, and was associated with dyslipidaemia. Further studies should be performed to confirm this result and to elucidate the role of SIRT1 in lipid metabolism.     

Characterization of the 3'UTR of the BTD gene and identification of regulatory elements and microRNAs

Reduced biotinidase activity is associated with a spectrum of deficiency ranging from total deficiency to heterozygous levels, a finding that is not always explained by the pathogenic variants observed in the BTD gene. The investigation of miRNAs, regulatory elements and variants in the 3’UTR region may present relevance in understanding the genotype-phenotype association. The aims of the study were to characterize the regulatory elements of the 3’UTR of the BTD gene and identify variants and miRNAs which may explain the discrepancies observed between genotype and biochemical phenotype. We evaluated 92 individuals with reduced biotinidase activity (level of heterozygotes = 33, borderline = 35, partial DB = 20 or total DB= 4) with previously determined BTD genotype. The 3’UTR of the BTD gene was Sanger sequenced. In silico analysis was performed to identify miRNAs and regulatory elements. No variants were found in the 3’UTR. We found 97 possible miRNAs associated with the BTD gene, 49 predicted miRNAs involved in the alanine, biotin, citrate and pyruvate metabolic pathways and 5 genes involved in biotin metabolism. Six AU-rich elements were found. Our data suggest variants in the 3''UTR of BTD do not explain the genotype-phenotype discrepancies found in Brazilian individuals with reduced biotinidase.