Variação genética e desempenho de progênies de Pinus caribaea var. hondurensis para produção de madeira e resina

Pós-graduação em Agronomia - FEIS

Parâmetros genéticos para características indicadoras de eficiência reprodutiva e produtiva de ovinos da raça Santa Inês

Pós-graduação em Genética e Melhoramento Animal - FCAV

Avaliação da influência do caráter lignotúber sobre características silviculturais em testes de progênies de Eucalyptus spp

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da influência do caráter lignotúber sobre características silviculturais em testes de progênies de Eucalyptus spp

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Grain yield variation and association of major traits in brown-seeded genotypes of tef [Eragrostis tef (Zucc.)Trotter]

Background Tef [Eragrostis tef (Zucc.) Trotter] is the major cereal crop of Ethiopia where it is annually cultivated on more than three million hectares of land by over six million small-scale farmers. It is broadly grouped into white and brown-seeded type depending on grain color, although some intermediate color grains also exist. Earlier breeding experiments focused on white-seeded tef, and a number of improved varieties were released to the farming community. Thirty-six brown-seeded tef genotypes were evaluated using a 6 × 6 simple lattice design at three locations in the central highlands of Ethiopia to assess the productivity, heritability, and association among major pheno-morphic traits. Results The mean square due to genotypes, locations, and genotype by locations were significant (P < 0.01) for all traits studied. Genotypic and phenotypic coefficients of variations ranged from 2.5 to 20.3 % and from 4.3 to 21.7 %, respectively. Grain yield showed significant (P < 0.01) genotypic correlation with shoot biomass and harvest index, while it had highly significant (P < 0.01) phenotypic correlation with all the traits evaluated. Besides, association of lodging index with biomass and grain yield was negative and significant at phenotypic level while it was not significant at genotypic level. Cluster analysis grouped the 36 test genotypes into seven distinct classes. Furthermore, the first three principal components with eigenvalues greater than unity extracted 78.3 % of the total variation. Conclusion The current study, generally, revealed the identification of genotypes with superior grain yield and other desirable traits for further evaluation and eventual release to the farming community.

Advantage of single-trial models for response to selection in wheat breeding multi-environment trials

An investigation was conducted to evaluate the impact of experimental designs and spatial analyses (single-trial models) of the response to selection for grain yield in the northern grains region of Australia (Queensland and northern New South Wales). Two sets of multi-environment experiments were considered. One set, based on 33 trials conducted from 1994 to 1996, was used to represent the testing system of the wheat breeding program and is referred to as the multi-environment trial (MET). The second set, based on 47 trials conducted from 1986 to 1993, sampled a more diverse set of years and management regimes and was used to represent the target population of environments (TPE). There were 18 genotypes in common between the MET and TPE sets of trials. From indirect selection theory, the phenotypic correlation coefficient between the MET and TPE single-trial adjusted genotype means [r(p(MT))] was used to determine the effect of the single-trial model on the expected indirect response to selection for grain yield in the TPE based on selection in the MET. Five single-trial models were considered: randomised complete block (RCB), incomplete block (IB), spatial analysis (SS), spatial analysis with a measurement error (SSM) and a combination of spatial analysis and experimental design information to identify the preferred (PF) model. Bootstrap-resampling methodology was used to construct multiple MET data sets, ranging in size from 2 to 20 environments per MET sample. The size and environmental composition of the MET and the single-trial model influenced the r(p(MT)). On average, the PF model resulted in a higher r(p(MT)) than the IB, SS and SSM models, which were in turn superior to the RCB model for MET sizes based on fewer than ten environments. For METs based on ten or more environments, the r(p(MT)) was similar for all single-trial models.

Effects of the orientation of the mountainside, altitude and varieties on the quality of the coffee beverage from the "Matas de Minas" region, brazilian Southeast.

Based upon qualitative parameters experiments, this study aims to investigate how the elements of the environment, where the coffee is produced, contribute to the final quality of the product. For the analyses, it was used approximately one kilogram of coffee cherry samples collected in 14municipalities previously chosen on the East side of the Minas Gerais State, Brazil. The coffee cherry samples were collected and analyzed for each of the two varieties in four levels of altitude for each exposure side of the mountain in relation to the Sun. The quality of the coffee was evaluated through the analysis of its physical characteristics and sensory analysis, popularly known as "Test of drink or Cupping" carried out by three tasters that belonging to the group of Q -Graders, according to the rules of national and international competitions of the Brazilian Association of Special Coffees (BSCA). Were performed analysis by means descriptive statistics, analysis of variance and multivariate analysis, all of them aiming to study the individual sensor y characteristics of quality of the coffee beverage from the ?Matas de Minas? region. Path coefficient analysis also was carried out for the partition of the phenotypic correlation coefficients into measures of direct and indirect effects, in order to determine the individual sensory characteristics that playeda major role in the beverage final score. The results demonstrat e that it is not possible to concl usively establish the differences among coffees evaluated with basis on varieties and environmental factors previously cited. It can be concluded that it is not recommended to associate the quality of coffee only to a specific factor whether from the environment or being it a specific of the culture of coffee. However, the cafes that were evaluated had intrinsic quality, which were derived from the specific characteristics of the ?Matas de Minas? region where they were grown.

Comparative genomics of Brachyspira pilosicoli strains: genome rearrangements, reductions and correlation of genetic compliment with phenotypic diversity.

Background. The anaerobic spirochaete Brachyspira pilosicoli causes enteric disease in avian, porcine and human hosts, amongst others. To date, the only available genome sequence of B. pilosicoli is that of strain 95/1000, a porcine isolate. In the first intra-species genome comparison within the Brachyspira genus, we report the whole genome sequence of B. pilosicoli B2904, an avian isolate, the incomplete genome sequence of B. pilosicoli WesB, a human isolate, and the comparisons with B. pilosicoli 95/1000. We also draw on incomplete genome sequences from three other Brachyspira species. Finally we report the first application of the high-throughput Biolog phenotype screening tool on the B. pilosicoli strains for detailed comparisons between genotype and phenotype. Results. Feature and sequence genome comparisons revealed a high degree of similarity between the three B. pilosicoli strains, although the genomes of B2904 and WesB were larger than that of 95/1000 (~2,765, 2.890 and 2.596 Mb, respectively). Genome rearrangements were observed which correlated largely with the positions of mobile genetic elements. Through comparison of the B2904 and WesB genomes with the 95/1000 genome, features that we propose are non-essential due to their absence from 95/1000 include a peptidase, glycine reductase complex components and transposases. Novel bacteriophages were detected in the newly-sequenced genomes, which appeared to have involvement in intra- and inter-species horizontal gene transfer. Phenotypic differences predicted from genome analysis, such as the lack of genes for glucuronate catabolism in 95/1000, were confirmed by phenotyping. Conclusions. The availability of multiple B. pilosicoli genome sequences has allowed us to demonstrate the substantial genomic variation that exists between these strains, and provides an insight into genetic events that are shaping the species. In addition, phenotype screening allowed determination of how genotypic differences translated to phenotype. Further application of such comparisons will improve understanding of the metabolic capabilities of Brachyspira species.

Phenotypic correlations among meat quality traits in broilers

The goals of this research were to estimate the phenotypic correlations among various meat quality traits from a male broiler line and to describe the relation among these variables. Phenotypical correlations were determined among quality traits, isolating the effects of slaughter date, the age of the mother and sex. The evaluated traits were pH measurements taken at time 0 and at 6 and 24 hours after slaughtering, color parameters, water loss due to exudation, thawing and cooking of the meat, and shear force. Important associations (P<0.01) were found to be significant and, in most cases, weak or moderate, varying from -0.35 to 0.28. The initial pH of the meat was not associated (P>0.05) to the other traits of the meat, whereas the pH at 24 hours after slaughter was able of directly interfering with the attributes of the meat, since this trait was inversely related with lightness and water losses, which indicates an effect of pH fall along 24h after slaughtering on protein denaturation. This study demonstrates that the variables of poultry meat quality are related and that there is a phenotypical association between lightness and cooking losses and the other attributes of the meat. The pH at 24 hours after slaughtering, lightness and cooking losses could be efficient meat quality indicators in this broiler line.

A New Mouse Model for Marfan Syndrome Presents Phenotypic Variability Associated with the Genetic Background and Overall Levels of Fbn1 Expression

Marfan syndrome is an autosomal dominant disease of connective tissue caused by mutations in the fibrillin-1 encoding gene FBN1. Patients present cardiovascular, ocular and skeletal manifestations, and although being fully penetrant, MFS is characterized by a wide clinical variability both within and between families. Here we describe a new mouse model of MFS that recapitulates the clinical heterogeneity of the syndrome in humans. Heterozygotes for the mutant Fbn1 allele mg Delta(loxPneo), carrying the same internal deletion of exons 19-24 as the mg Delta mouse model, present defective microfibrillar deposition, emphysema, deterioration of aortic wall and kyphosis. However, the onset of a clinical phenotypes is earlier in the 129/Sv than in C57BL/6 background, indicating the existence of genetic modifiers of MFS between these two mouse strains. In addition, we characterized a wide clinical variability within the 129/Sv congenic heterozygotes, suggesting involvement of epigenetic factors in disease severity. Finally, we show a strong negative correlation between overall levels of Fbn1 expression and the severity of the phenotypes, corroborating the suggested protective role of normal fibrillin-1 in MFS pathogenesis, and supporting the development of therapies based on increasing Fbn1 expression.

Genetic variation for anatomic traits and volume shrinkage and their correlation with wood basic density in an Eucalyptus camaldulensis Dehn base population

Eucalyptus camaldulensis has great importance in Brazil because of their phenotypic plasticity for different environmental conditions, as soils, altitudes and rainfall. This study is an investigation of a base population of E. camaldulensis from Australia through a progeny test implanted in Selviria, MS. The trial was established in a randomized block design, with 25 families and 60 replications of single tree plots. Genetic parameters for anatomic traits and volume shrinkage were estimated, as well as their correlations with wood basic density. No significant differences among progenies were observed for the traits studied. The additive genetic variation coefficient at individual and among progeny levels ranged from low (0.26%) to high (16.98%). The narrow sense heritability at individual and family means levels also ranged from low (0.01) to high (0.87). This indicates that some traits are under strong genetic control and can be improved by selection. In the present situation, in order to attain the highest genetic gains, the sequential selection among and within progeny would be recommended.

Exome sequencing extends the phenotypic spectrum for ABHD12 mutations: from syndromic to nonsyndromic retinal degeneration.

OBJECTIVE: To identify the genetic causes underlying autosomal recessive retinitis pigmentosa (arRP) and to describe the associated phenotype. DESIGN: Case series. PARTICIPANTS: Three hundred forty-seven unrelated families affected by arRP and 33 unrelated families affected by retinitis pigmentosa (RP) plus noncongenital and progressive hearing loss, ataxia, or both, respectively. METHODS: A whole exome sequencing (WES) analysis was performed in 2 families segregating arRP. A mutational screening was performed in 378 additional unrelated families for the exon-intron boundaries of the ABHD12 gene. To establish a genotype-phenotype correlation, individuals who were homozygous or compound heterozygotes of mutations in ABHD12 underwent exhaustive clinical examinations by ophthalmologists, neurologists, and otologists. MAIN OUTCOME MEASURES: DNA sequence variants, best-corrected visual acuity, visual field assessments, electroretinogram responses, magnetic resonance imaging, and audiography. RESULTS: After a WES analysis, we identified 4 new mutations (p.Arg107Glufs*8, p.Trp159*, p.Arg186Pro, and p.Thr202Ile) in ABHD12 in 2 families (RP-1292 and W08-1833) previously diagnosed with nonsyndromic arRP, which cosegregated with the disease among the family members. Another homozygous mutation (p.His372Gln) was detected in 1 affected individual (RP-1487) from a cohort of 378 unrelated arRP and syndromic RP patients. After exhaustive clinical examinations by neurologists and otologists, the 4 affected members of the RP-1292 had no polyneuropathy or ataxia, and the sensorineural hearing loss and cataract were attributed to age or the normal course of the RP, whereas the affected members of the families W08-1833 and RP-1487 showed clearly symptoms associated with polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract (PHARC) syndrome. CONCLUSIONS: Null mutations in the ABHD12 gene lead to PHARC syndrome, a neurodegenerative disease including polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract. Our study allowed us to report 5 new mutations in ABHD12. This is the first time missense mutations have been described for this gene. Furthermore, these findings are expanding the spectrum of phenotypes associated with ABHD12 mutations ranging from PHARC syndrome to a nonsyndromic form of retinal degeneration.

When genetic load does not correlate with phenotypic spectrum: lessons from the GnRH receptor (GNRHR).

CONTEXT: A broad spectrum of GnRH-deficient phenotypes has been identified in individuals with both mono- and biallelic GNRHR mutations. OBJECTIVE: The objective of the study was to determine the correlation between the severity of the reproductive phenotype(s) and the number and functional severity of rare sequence variants in GNRHR. SUBJECTS: Eight hundred sixty-three probands with different forms of GnRH deficiency, 46 family members and 422 controls were screened for GNRHR mutations. The 70 subjects (32 patients and 38 family members) harboring mutations were divided into four groups (G1-G4) based on the functional severity of the mutations (complete or partial loss of function) and the number of affected alleles (monoallelic or biallelic) with mutations, and these classes were mapped on their clinical phenotypes. RESULTS: The prevalence of heterozygous rare sequence variants in GNRHR was significantly higher in probands vs. controls (P < 0.01). Among the G1-G3 groups (homozygous subjects with successively decreasing severity and number of mutations), the hypogonadotropic phenotype related to their genetic load. In contrast, subjects in G4, with only monoallelic mutations, demonstrated a greater diversity of clinical phenotypes. CONCLUSIONS: In patients with GnRH deficiency and biallelic mutations in GNRHR, genetic burden defined by severity and dose is associated with clinical phenotype. In contrast, for patients with monoallelic GNRHR mutations this correlation does not hold. Taken together, these data indicate that as-yet-unidentified genetic and/or environmental factors may combine with singly mutated GNRHR alleles to produce reproductive phenotypes.

Evaluation of diagnostic molecular markers for DUS phenotypic assessment in the cereal crop, barley (Hordeum vulgare ssp. vulgare L.)

The deployment of genetic markers is of interest in crop assessment and breeding programmes, due to the potential savings in cost and time afforded. As part of the internationally recognised framework for the awarding of Plant Breeders’ Rights (PBR), new barley variety submissions are evaluated using a suite of morphological traits to ensure they are distinct, uniform and stable (DUS) in comparison to all previous submissions. Increasing knowledge of the genetic control of many of these traits provides the opportunity to assess the potential of deploying diagnostic/perfect genetic markers in place of phenotypic assessment. Here, we identify a suite of 25 genetic markers assaying for 14 DUS traits, and implement them using a single genotyping platform (KASPar). Using a panel of 169 UK barley varieties, we show that phenotypic state at three of these traits can be perfectly predicted by genotype. Predictive values for an additional nine traits ranged from 81 to 99 %. Finally, by comparison of varietal discrimination based on phenotype and genotype resulted in correlation of 0.72, indicating that deployment of molecular markers for varietal discrimination could be feasible in the near future. Due to the flexibility of the genotyping platform used, the genetic markers described here can be used in any number or combination, in-house or by outsourcing, allowing flexible deployment by users. These markers are likely to find application where tracking of specific alleles is required in breeding programmes, or for potential use within national assessment programmes for the awarding of PBRs.

Salmoninae Commensal Bacteria Show a Positive Correlation Between Antibiotic Resistance and Mercury Resistance Profiles

Bacterial isolates from natural sites with high toxic and heavy metal contamination more frequently contain determinants for resistance to antimicrobials. Natural strains were isolated from the ingesta and external slime of Salmo salar (Linnaeus, 1758) and Salvelinusjontinalis (Mitchell, 1814). Fish specimens were acquired from Casco Bay hatcheries, Casco, ME where there is no history of antibiotic use. Seventy-nine bacterial strains, including many well-documented salmonid commensals (an association from which the fish derives no benefit), were identified using 165 rRNA gene sequencing. Mercury resistant isolates were selected for initially on 25μM HgCI2. Strains were then grown at 20-24°C on Trypticase Soy Agar (TSA) plates containing 0-1000μM HgCl2 or 0-130μM Phenyl Mercuric Acetate (PMA). Mercury in the hatchery feed water due to ubiquitous non-point source deposition has selected for the mercury resistance observed in bacterial strains. Antibiotic resistance determinations, as measured by Minimum Inhibitory Concentration MIC) assays were performed on the 79 bacterial isolates using Sensititrel antimicrobial susceptibility panels. A positive linear correlation between the mercury (pMA and HgCl2) MIC's and antibiotic resistance for all observed strains was demonstrated. Conjugation experiments with Pseudomonas, Aeromonas, and Azomonas donors confirmed phenotypic transfer of penicillin and cephem resistances to Escherichia coli DH5a recipients. Conjugation experiments with Pseudomonas donors showed minimal transfer of tetracycline and minoglycoside resistances to Escherichia coli DH5a recipients. Our study suggests that the accumulation of antimicrobial resistances observed in these natural bacterial populations may be due to the indirect selective pressure exerted by environmental mercury.