Research Article

Table of Contents | Genet. Mol. Res. 2020 (4)

Displaying 1 - 10 of 10
Research Article

Information on genetic parameters is essential to obtain rapid progress in the development of cultivars, which is of great interest to the potato processing industry in Brazil, as the consumption of processed potatoes has increased significantly in the last 10 years. Unfortunately the lack of raw material of quality limits its growth. Thus, the objective of this study was to estimate genetic parameters of characters of importance in the development of potato cultivars aimed at this agroindustry, in a hybrid population of 20 potato families in Embrapa's Potato Breeding Program. The experiment was carried out at Embrapa, Pelotas, RS, in two growing seasons. The design was randomized blocks with four replications; each repetition was composed of five genotypes of each family, and each plot was represented by five plants of each genotype. After harvesting, the tubers of each plot were evaluated for industrial quality, yield, external physiological defects and external appearance of tubers. The estimates of the variance components and genetic parameters (Restricted Maximum Likelihood) were obtained using the Harmonic Mean of the Relative Performance of the Genetic Values. There was an estimated high broad sense heritability for film texture (TEX) and glucose (GLUC); and moderate for secondary growth (GRO), shape (SHA), dry mass (DM), general appearance (APP), percentage of commercial tubers mass (PCM), curvature (CUR), size uniformity (SIU), shape uniformity (SHU) ) and mean tuber mass (MTM). GLUC, SHA, TEX and APP showed superiority of the genotypic coefficient of variation (CVg) in relation to the residual coefficient of variation (CVe), for these characters. The highest CVg - CVe ratios were obtained for SIU, PCM, SHU, DM and GRO. In the light of this study, it is suggested that strong selection pressure can be applied to the characters GLUC, SHA, TEX and APP, and moderate selection pressure to SIU, PCM, SHU, DM, and GRO.

Genet. Mol. Res. 19(4): GMR18597
DOI: 10.4238/gmr18597
Research Article

Comprehending the constitution of early biological metabolism is indispensable for the understanding of the origin and evolution of life on Earth.  Here, we analyzed the structural proteome before the Last Universal Common Ancestor based on the reconstruction of the ancestral sequences and structure of proteins involved in glycolysis/gluconeogenesis. The results are compatible with the notion that the first portions of the proteins were the areas homologous to the present-day catalytic sites. These “proto-proteins” had a simple function: binding to cofactors. Upon the accretion of new elements to the structure, the catalytic function could have emerged. Also, the first structural motifs might have have influenced the various types of proteins that are produced in modern organisms.

Genet. Mol. Res. 19(4): GMR18699
DOI: 10.4238/gmr18699
Research Article

The demand for quality vegetable oil, such as castor oil, has been increasing significantly due to its great applicability in the cosmetic and industrial sector, especially with the advent of biodiesel. Castor bean produces a non-edible oil, with unique chemical properties, which makes it potentially useful for the production of cosmetics, aircraft lubricants and biodiesel. Breeding programs aimed at increasing the oil content in castor bean seeds are of paramount importance to meet the requirements of this market. In view of the above, we examined the genetic variability of elite castor bean strains through joint analysis of the oil content trait and TRAP (Target Region Amplification Polymorphism) molecular markers. This analysis was performed using the means for seed oil content of 40 elite castor bean strains, developed by the breeding program of the Genetic Improvement and Biotechnology Unit of the Federal University of Recôncavo da Bahia, together with genotyping of this population by means of 44 combinations of TRAP primers (fixed and arbitrary primers). Genetic dissimilarity between the strains was calculated through the Gower dissimilarity index, using the UPGMA clustering method. The means for oil content rangeed from 39.10 (UFRB 36) to 55.39% (UFRB 209), demonstrating that there is genetic variability among the strains. The 44 TRAP combinations enabled the identification of 380 fragments, 61% of which were polymorphic. The joint analysis formed three clusters, showing that there is genetic divergence among these elite strains. Therefore, joint analysis of the seed oil content trait and TRAP markers is efficient to evaluate the genetic dissimilarity in castor bean strains, demonstrating potential for the breeding program of the species.

Genet. Mol. Res. 19(4): GMR18688
DOI: 10.4238/gmr18688
Research Article

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the destruction of pancreatic β-cells. Interleukins such as interleukin 18 (IL-18) and protein tyrosine phosphatase, nonreceptor type 22 (PTPN22) have been found to be associated with immune related diseases. We investigated a possible association of polymorphisms in IL-18 gene rs1946518 and PTPN22 rs2476601 with T1DM diagnosed in children (aged ≤14 years) and adults (aged ≥18 years) via a case-control study. In Euro-Brazilian children (n = 320) and adults (n = 291), patients with T1DM and healthy individuals (control) were genotyped for rs1946518 and rs2476601 using fluorescent probes (Taqman system). All groups were in the Hardy-Weinberg equilibrium. No significant differences were observed in the genotypes and allele frequencies for both polymorphisms. For the IL-18 rs1946518 A-allele, the minor allele frequencies for children, adults, healthy individuals, and T1DM were 49% (95% CI, 43.0–55.0), 47.5% (40–52), 47.9% (43–53), and 51% (45–57), respectively. For the PTPN22 rs2476601 T-allele in adults, controls and T1DM had frequencies of 7.3% (4–10) and 6.7% (4–10). In conclusion, these polymorphisms were not associated with T1DM onset in children or adults in this population.

Genet. Mol. Res. 19(4): GMR18686
DOI: 10.4238/gmr18686
Research Article

One of the pests that infests the corn crop (Zea mays) in Brazil is the fall armyworm (Spodoptera frugiperda, Lepdoptera: Noctuidae), considered its most important pest because of the significant damage produced. The use of resistant cultivars is an efficient control method. The objective of this work was to evaluate the mechanisms of resistance of non-feeding preference and antibiosis of newly hatched caterpillars on leaves of inbred corn lineages, derived from populations of commercial hybrid origins, Creole populations and semi-exotic populations. The no-choice non-feeding preference test was conducted in the laboratory, with three replications per 24 hours, using leaves of 169 corn lineages. For the antibiosis test, lineages that had a smaller leaf area consumed were selected and also lineages that had a larger leaf area consumed, which were sown in a greenhouse to proceed with leaf harvesting and the tests. Newly hatched larvae of S, frugiperda were fed daily, through the provision of leaves of the lineages evaluated with regard to biomass and length after 5, 10 and 15 days feeding.  Besides presenting a non-feeding preference mechanism of resistance, lineages 94 and 137 also led to a change in the development of caterpillars, being promising to increase the efficiency of resistant cultivars in breeding programs.

Genet. Mol. Res. 19(4): GMR18446
DOI: 10.4238/gmr18446
Research Article

Pancreatic adenocarcinoma (PA) is one of the most aggressive malignant tumors of the digestive tract, with a five-year survival rate of 5%. Early detection offers better possibilities of cure; however, in early stages it does not present symptoms, making the management of these patients difficult. The most commonly used biomarker for diagnosis of PA is serum CA19-9, which has a sensitivity between 70 and 80%, although, with less than 50% specificity, due to its expression in various other types of cancer. The reduced rate of apoptosis plays a crucial role in carcinogenesis, in which the cytotoxic attack and the effectiveness of pharmacological treatment are reduced. Therefore, it would be useful to associate the biomarker CA19-9 with other molecular tools to increase the accuracy of the diagnosis, such as microRNAs (miRNAs) that target apoptotic genes. The association between the expression profile of anti-apoptotic microRNAs (miRNA-15a and miRNA-16), pro-apoptotic microRNAs (miRNA-21, miRNA-221 and miRNA-222) and serum CA19-9 was evaluated for the diagnosis of pancreatic ductal adenocarcinoma. Twenty pancreatic tumor tissue samples, after microdissection from patients diagnosed with pancreatic adenocarcinoma, were studied. As a control, seven samples of normal pancreas from cadaveric donors or patients undergoing pancreatic resection due to trauma were used. Serum CA19-9 was measured and the expression analysis of miRNA-21, miRNA-221, miRNA-222, miRNA-15a and miRNA-16 was measured using real-time quantitative PCR. The usefulness of pro-apoptotic and anti-apototic microRNAs alone or in association with CA19-9 in the diagnosis of PA was evaluated. The expression of miRNA-21 was significantly associated with PA, when compared with control samples. There was no significant difference in the expression of the other miRNAs. We conclude that association of CA19-9 and microRNA-21expression would increase sensitivity and accuracy in the diagnosis of PA.

Genet. Mol. Res. 19(4): GMR18645
DOI: 10.4238/gmr18645
Research Article

Ningxia Tan sheep meat is tender, has no strong smell, a delicious taste, and even fat distribution. Intramuscular fat (IMF) content and the composition of fatty acid (FA) both are important factors associated with meat quality, and are also important for meat tenderness and flavor assessment. We examined the correlation of candidate genes expression with these factors in four muscle tissues, including longissimus dorsi, triceps, biceps and supraspinatus from Tan sheep. The IMF and FA composition in the different muscle tissues were measured and associated with mRNA expression of related genes (PPARγ, C/EBPα, FAS, LPL, FABP4, and ACC). IMF content in longissimus dorsi muscle was 45.4% higher than that in triceps brachii (P < 0.05), 48.4% higher than that in biceps femoris, and 20.1% higher than that in supraspinatus. PPARγ, C/EBPα, FAS and LPL mRNA levels in supraspinatus were significantly different among longissimus dorsi muscle, biceps femoris and triceps brachii. There was significant positive correlation between IMF content and the relative mRNA expression of PPARγ, C/EBPα, FAS, LPL, FABP4 and ACC in longissimus dorsi muscle. The ratio of polyunsaturated fatty acids to saturated fatty acid was positively and significantly correlated with C/EBPα and ACC mRNA levels, and negatively and significantly correlated with FAS and FABP4 mRNA levels. Omega-6 fatty acid (ω6)/omega-3 fatty acid (ω3) ratio was positively and significantly correlated with C/EBPα, FAS and LPL mRNA levels, but negatively and significantly correlated with FAS and PPARγ mRNA levels. These correlations indicate that PPARγ, C/EBPα, FAS, LPL, FABP4, and ACC are key candidate genes for fatty deposits and the components and contents of FA in sheep, and the evaluation and functional verification of these genes may be useful for improving the meat quality of Tan sheep.

Genet. Mol. Res. 19(4): GMR18550
DOI: 10.4238/gmr18550
Research Article

The development of oral cancer results from interactions between genetic and environmental factors. Glutathione-S-transferase gene null polymorphisms have a strong impact on the detoxification of carcinogens; therefore they are expected to be related to oncogenic risk, including oral cancer. Various studies have evaluated a possible association of GSTT1 and GSTM1 null genotypes with oral cancer, including their relationship with tobacco smoking; though the findings have been inconsistent. We analyzed the available publications concerning association of tobacco smoking and GSTT1 and GSTM1 null polymorphisms and how they relate to the risk of developing oral cancer. A systematic review of the literature was conducted in the PubMed database using combinations of the following descriptors and Boolean operators ‘GSTM1 and GSTT1’, [AND] ‘oral cancer’, [AND] ‘polymorphism’. A meta-analysis of GSTT1 and GSTM1 null polymorphisms in patients with oral cancer (cases) and cancer-free individuals (controls) from each of the studies was performed. The data of each study were analyzed, and the odds ratio, the 95% confidence interval, and the number of patients were determined for each study and for all studies combined. The number of individuals analyzed was 7,839, 44.3% presenting with oral cancer and 55.7% healthy controls. The meta-analysis showed that GSTT1 and GSTM1 were associated with protection against oral cancer. A significant association of GSTT1 and GSTM1 null polymorphisms with an increased risk of developing oral cancer was observed. These findings point to a synergistic relationship between environmental and genetic factors in the development of oral cancer tumors.

Genet. Mol. Res. 19(4): GMR18712
DOI: 10.4238/gmr18712
Research Article

Microsatellite markers, also known as single sequence repeats (SSRs), are highly polymorphic, fast evolving, and regarded as neutral markers. Due to these traits, they have been widely used in population studies. The development of SSRs for a given species opens possibilities for their application in population studies of other species that are phylogenetically related. We tested 16 primer pairs developed for Drosophila sturtevanti and the transferability test of them in 14 species of the saltans group of Drosophila. The optimal amplification conditions were established using the DNA of 15 D. sturtevanti males. Among the primers pairs developed, 13 have successful in the amplification for D. sturtevanti. And in the transferability test, the total percentage of transfer was nearly 50%. The species with the highest success rates of heterologous amplification were in the sturtevanti subgroup. Two microsatellite markers amplified in all the species, while one would not amplify for any of the saltans group species. These data demonstrate the usefulness of testing transferability of genetic markers, which may be used in studies of genetic diversity and population structure of D. sturtevanti and other species of the saltans group of Drosophila.

Genet. Mol. Res. 19(4): GMR18700
DOI: 10.4238/gmr18700
Research Article

Analysis of the relationship of oat grain chemical components with productivity can yield information that determines crop production strategies. The market values high protein grain, but production and other nutritional components may be affected in the effort to increase protein levels. The objective of this study was to determine how the dynamics of the components of oat grain chemical composition relate to productivity when adding nitrogen to the soil, in order to develop nutrient management strategies that can combine productivity with grain quality.  The study was conducted from 2011 to 2016 in Augusto Pestana, Brazil, in a randomized block design with four replications in a 4x2 factorial design for nitrogen rates (0, 30, 60 and 120 kg.ha-1) and standard biotype oat cultivars used on a commercial scale (Barbarasul and Brisasul) in two succession systems soybean/oat and corn/oat, totaling 64 experimental units. The nitrogen doses were applied at the phenological stage of expanded fourth leaf using urea. The increase of nitrogen fertilization for topdressing promoted increase of the total protein of oat grains and reduction of the total fiber in both soybean/oat and corn/oat systems. Higher levels of grain protein due to nitrogen fertilization reduced grain production, regardless of the cropping system.

Genet. Mol. Res. 19(4): GMR18569
DOI: 10.4238/gmr18569