Modelos lineares generalizados mistos na avaliação genética da prenhez precoce na raça Nelore

This study aimed to use the generalized linear models with probit and logit link function to evaluate early pregnancy, and to observe the effects on genetic variability and on sire selection when different ages are adopted in the definition of this trait. Early pregnancy was studied at 15 (EP15), and 21 (EP21) months. The analysis was done in R software. Pearson correlations (PC), between genetic predicted values and percentage of bulls in common considering only 10% of bulls with higher genetic values (TOP 10), between classification by logit and probit models and in each model among EP15 and EP21, were calculated. The heritability for EP15 and EP21 were close between models, except for EP15 using probit link function. PC and TOP10 among models were high. The Akaike and Bayesian criteria reported was similar between models. TOP10, considering the same model, among EP15-EP21 were moderated between EP15-EP21.

Meta-análise de parâmetros genéticos relacionados ao consumo alimentar residual e a suas características componentes em bovinos

The objective of this work was to estimate, by meta-analysis, the heritability (h(2)) and the genetic (r(g)) and phenotypic (r(f)) correlations of residual feed intake (RFI), and of its component traits in beef cattle from 19 breeds or genetic groups. Twenty-two scientific papers published from 1963 to 2011, from eight countries, totaling 52,637 cattle of ages from 28 days up to slaughter, were evaluated. The estimates of RFI, dry matter intake (DMI), average daily gain (ADG) and metabolic weight (BW0.75) were weighted by the inverse of sample variance. The variation between studies of h(2) for each trait was analyzed by weighted least squares. The effects of sex, country and breed were significant for h(2) of RFI, explaining 67% of variation between studies. For DMI, country and breed effects were significant and explained 96% of variation. Pooled estimates of h(2) were: 0.255+/-0.008, 0.278+/-0.012, 0.321+/-0.015, and 0.397+/-0.032 for RFI, DMI, ADG and BW0.75, respectively. Pooled estimates of genetic and phenotypic correlations were low between RFI and ADG and between RFI and BW0.75 (from -0.021+/-0.034 to 0.025+/-0.035), and moderate between RFI and DMI (0.636+/-0.035 and 0.698+/-0.041) and between DMI, ADG and BW0.75 (0.441+/-0.062 to 0.688+/-0.032). The trait RFI has lower heritability estimates than its components.

Estimativa da mudança genética na produção de leite e gordura em bovinos da raça Holandesa

The objective of this study was to estimate the genetic trends of the milk and fat yield in three herds maintained in São Paulo State, Brazil. The estimation of genetic, environmental and phenotypic trends were based on 716 first lactations. The cows were sired by 134 bulls. The statistical models included the fixed effects of herds, kind of gestation, season and year of the calving, age of the cow at calving, besides the random effect of the bulls. The statistical analyses, by the last squares method showed effects for bulls, herds and age of the cows on milk and fat yield. The genetic, environmental and phenotypic trends estimated were -10.20; 6.74 and -3.46 kg for milk yield and -1.90; 2.20 and 0.12 kg for fat yield.

Relevância da genética na etiologia do autismo

Autism constitutes one of the most important pathologies of the pervasive developmental disorders (PDDs). It has early age-onset and is characterized by delay and deviance of social, communicative and cognitive development. Today, the presence of genetic factors in its etiology is well known, with familial recurrence of autism and other psychiatric conditions. Autism does not have usual Mendelian inheritence and presents genetic heterogeneity. Strong association has been found between autism and the fragile X syndrome (FMR-1 gene) and with tuberous sclerosis (Bourneville's syndrome). However, many different chromosomal abnormalities were recently described in autistic patients, mainly of chromosome 7 and 15. There are some genes on 15q11-q13 whose products have expression in the central nervous system, mainly synapses, which are subunits of neurotransmitters or ion channels (UBE3A, GABRA5, GABRB3, GABRG3, CHRNA7 e ITO). Some regions of chromosome 7 also have important developmental genes, as EN-2 and HOXA, which act on central nervous system formation. There seems then to exist genes associated with autism etiology on chromosomes 7,15 and X. The detailed study of these chromosomes can produce knowledgment about the biological mechanisms involved in this disturbance.

Avaliação da variabilidade genética em quatro gerações de Eucalyptus urophylla S.T. Blake por meio do marcador molecular RAPD

Molecular markers have gradually replaced morphological markers in population studies. The advantages of molecular markers are the speed and precision of evaluations, mainly for long cycle cultures, where determinate traits can take years to manifest. The principle objectives of this research were to assess variability and genetic distances in four generations of Eucalyptus urophylla and provide data that help with the continued improvement of these materials. The populations can be found at the Experimental Forestry Sciences Station, Anhembi, SP, belonging to the College of Agriculture Luiz de Queiroz of São Paulo University. The initial base population was introduced by seeds collected in indonesia and designated P0 generation. The subsequent segregated generations, derivatives of recombination starting with open pollination, were designated P1, P2, and P3. One hundred and seventy four individual trees representing the four generations were analysed. The RAPD technique allowed the identification of 86 loci that were analysed with the Jaccard Coefficient, generating a genetic similarity matrix, permitting the estimation of genetic distances. The genetic distance of generation PO was 0.3338333, P1 was 0.336824, P2 was 0.40000, and P3 was 0.381093. In percentage terms the genetic distances between individuals grew in relation to base population, being 0.15% for generation P1, 18.93% for P2, and 13.31% for P3. This shows an increase in genetic variability with the advance of the program, despite the selective processes. From this came the belief that the initial base population was resulting from seed collection from isolated trees. These populations, although going through successive selections, had a high cross efficiency through satisfactory pollination, which then permitted genetic variation to increase, the outcome of effective recombination between individuals. Generations P2 and P3 gave a better perspective for the continuance of the improvement program due to the high number of different groups with standard genetic distances of 35%. The selections made between the diverse genetic groups allowed the efficient use of genetic variability evaluation.

Caracterização silvicultural, botânica e avaliação da variabilidade genética por meio do marcador molecular RAPD em um teste de progênies de Eucalyptus urophylla S. T. Blake

Molecular markers have recently been incorporated into genetic improvement programs. They are already considered as powerful tools with several different uses, for instance the monitoring of genetic variability in tree populations. The main objectives of this study were to evaluate genetic variability in Eucalyptus urophylla progenies and together with silvicultural and botanical information, provide assistance to the improvement program. The Eucalypts population is located at the Experimental Forestry Sciences Station, Anhembi, SP, which belongs to the College of Agriculture Luiz de Queiroz. Sixty-nine progenies were analysed representing one individual by family in open pollinated Eucalyptus urophylla trees. The RAPD technique allowed the identification of 72 loci that were analysed using Jaccard's Coefficient generating a genetic similarity matrix to permit estimation of genetic distances. The results obtained showed genetic distance between individuals of 0.40 with 12 groups of genetic variability using a standardised distance of 40%. The progenies showed different bark patterns, allowing the establishment of bark groups. The groups formed based on genetic distances obtained using DNA analysis did not correspond to those based on bark pattern. Genetic selection was simulated in which silvicultural and genetic variability data were linked, thus avoiding excessive variability losses. The simulation of controlled crossings allowed the maximum genetic difference to be obtained linked with height and individual bark roughness.

Estudo de modelo alternativo para estimação de componentes de (co)variância e predição de valores genéticos de características de crescimento em bovinos da raça Nelore

The objectives of this study were to estimate genetic parameters for non-standardized weights at nursing (PR120), at weaning (PR240), at yearling (PR365) and at post yearling (PR550), and to predict EPD's (expected progeny differences) for these traits using records from 29,769 Nellores. Covariance components and genetic parameters were estimated by mixed-model methodology, REML, using an animal model. Models for PR120, PR240, PR365 and PR455 included the random direct and maternal animal effects, the dam permanent environmental effect and the error. Fixed effects were contemporary group (CG) and age of cow at parturition (CIVP) and the covariate age of the calf at measuring. Two additional models for PR365, PR455 and PR550 analyses were used: the first included CG and CIVP, animal and maternal direct effect, residual and age of the calf (as covariate), and the second included CG and CIVP (as fixed effects), animal direct effect, residual and age of calf at measuring. Observed means±standard deviations were: 127±25kg (PR120); 191±34kg (PR240); 225±42kg (PR365); 266±51kg (PR455) and 310±56kg (PR550). From single-trait analyses, direct and maternal heritabilities for PR120, PR240, PR365 and PR455 were, respectively, .23 and .08; .19 and .10; .24 and .04; .30 and .04. Direct heritabilities were .39; .44 and .43, respectively, for PR365, PR455 and PR550. In the model without permanent effect, direct and maternal heritabilities for PR365, PR455 and PR550 were .25 and .08; .32 and .07; .38 and .03, respectively. When the estimates for standardized traits at the same period were compared, no differences in magnitude were found. Rank correlation had important changes when standardized and non-standardized traits were compared.

Estrutura genética de populações de Trichilia pallida Swartz (Meliaceae) por marcadores RAPD

Trichilia pallida Swartz is an Atlantic Forest shady climax tree of Meliaceae family that presents insecticide properties against chewing insects like as some family trees, making it interesting for forestry uses. Forty plants of Oito Pontas Farm population were collected in Bofete County, Santa Genebra Ecological Station in Campinas County, and Caetetus Ecological Station in Gélia County, all in the Sao Paulo State, Brazil. Leaf DNA analysis was used by RAPD method, that showed 10 highly polymorphic primers, with 72 dominant markers, used to estimate genetic diversity within and among populations. The polymorphism within populations varied from 90.3 to 97.2%, and the effective allele number varied from 1.46 ± 0.33 to 1.57 ± 0.33, while the average of genetic differentiation of populations varied from 0.27 ± 0.18 to 0, 33 ± 0.15. The gene diversity in the total population (H T) was 0.334 ± 0.02, while the average gene diversity within populations (H s) was 0.292 ± 0.017, and the coefficient of gene differentiation (G ST) was 0.125, Bofete and Campinas populations had the smallest Nei's genetic distance (0.049) and the distances of both with Gália were 0.117 and 0.107, respectively.

Variabilidade genética intrapopulacional em Myracrodruon urundeuva Fr. All. por marcador AFLP

Levels of genetic variability for in situ and ex situ genetic conservation were estimated in a population of Myracrodruon urundeuva using the PCR (polymerase chain reaction) technique with the AFLP (Amplified fragment-length polymorphism) genetic marker. Seeds for progeny tests were collected from 30 open-pollination trees (matrices) at Paulo de Faria Ecological Station - SP. From this genetic material, three progeny tests were installed on the Teaching and Research Farm of Ilha Solteira Faculty of Engineering - University of São Paulo State (UNESP), which is located in Selvlria - MS, Brazil. The analysis by genetic marker was conducted with three combinations of different starters EcoRl-Msel, resulting in a total number of 137 polymorphic bands, thus forming a table of binary data. These data were used for the analysis of genetic divergence and distance between progenies. High levels of genetic divergence were observed among families. Based on the Analysis of Molecular Variance (AMOVA), it was shown that 16.2% of genetic diversity is found among progenies and 83.8% within progenies, which suggests deviances of random matings. The grouping of progenies, based on genetic distances, suggests that progenies deriving from trees which are close to each other tend to be more similar. This, in turn, indicates that the population originating the seeds may be genetically structured.

Efeito do desbaste seletivo sobre a divergência genética em progênies de Pinus caribaea Morelet var. bahamensis

The objective of this work was to study the effect of selective thinning on the genetic divergence in progenies of Pinus caribaea var. bahamensis, aiming to identify the most productive and divergent progenies for the use of improvement program. The test of progenies containing 119 progenies and two commercial controls were planted in March 1990, using 11 × 11 square lattice design, sextuple, partially balanced, disposed in lineal plots with six trees in the spacing of 3,0 × 3,0m. 13 years after planting thinning was realized (selection for DBH), with 50% selection intensity based on Multi-effect index, leaving three trees per plot in all the experiment. The evaluations were done at four situations: A (before the thinning); B (thinned trees); C (remaining trees after thinning) and D (one year after thinning). The analyzed traits were: height, diameter at breast height (DBH), volume, form of stem and wood density. The genetic divergence among the progenies was studied with aid of the canonical variables and of clustering of Tocher method, using the generalized distance matrix of Mahalanobis (D2) as estimate of the genetic similarity. The progenies were grouped in four groups in situation A, fourteen in the situation B, two in the situation C and three in the situation D. The selective thinning of the trees within of the progenies caused a change in the genetic divergence among the progenies, genetically homogenizing the progenies, as demonstrated by the generalized distances of Mahalanobis, clustering of Tocher' and canonical variables methods. The thinning made possible a high uniformity in respect to the relative contribution of the traits for the total genetic divergence. The techniques of clustering were efficient to identify groups of divergent progenies for the use hybridization and little divergent progenies for the use in backcross program.

Variabilidade genética na porção codificadora para a proteína capsidial do Lettuce big-vein associated virus e Mirafiori lettuce big-vein virus provenientes de alface no Brasil

Lettuce big vein associated virus (LBVaV) and Mirafiori lettuce big vein virus (MLBVV) have been found in mixed infection in Brazil causing the lettuce big vein disease. Analysis of part of the coat protein (CP) gene of Brazilian isolates of LBVaV collected from lettuce, showed at least 93% amino acid sequence identity with other LBVaV isolates. Genetic diversity among MLBVV CP sequences was higher when compared to LBVaV CP sequences, with amino acid sequence identity ranging between 91% to 100%. Brazilian isolates of MLBVV belong to subgroup A, with one RsaI restriction site on the coat protein gene. There is no indication for a possible geografical origin for the Brazilian isolates of LBVaV and MLBVV.

Evaluación genética de búfalos de la raza Murrah para la producción de leche en el día de control y a los 305 días de lactancia

There were analyzed 4757 complete lactations of the Murrah breed, daughters of 187 bulls, with the goal of verifying the viability upon employing the test-day (PDLC), on substitution of the milk yield at 305th day of lactation (PL305), in the genetic evaluations. The components of variance for the PDLC1 to PDLC9 and for the PL305 were estimated in uni-traits analysis according to maximum restricted likelihood method. The used model included the genetic direct additive random effects, of residual and permanent environment. There were considered as fixed effects, the contemporary group and the number of milkings and the age of the cow at the moment of parity co-variable (quadratic and linear effect). The contemporary groups were constituted by the herd-year-month of control for the PDLC and by herd-year-epoch of parity for PL305. The estimates of heritability for the PDLC and PL305 were 0.12 to 0.23 and 0.22, respectively. The correlations of order of the predicted genetic values for the 187 bulls, obtained between the PDLC and the PL305, were from moderate to high, varying from 67.74 to 83.12. From the minimum selection of the 10% of the best bulls relating to the predicted genetic value for the PL305, the coincidence among the classification of these animals was over 68%, when evaluated by the PDLC3,PDLC4,PDLC5 and PDLC6. Upon selecting the 5% of the best animals that coincidence presented a lower value.

Variação genética para compostos bioquímicos em sementes de duas populações naturais de Genipa americana L.: 1-análises individuais e univariada

Brazil is one of the world's richest countries in forest biodiversity. This has a great importance for humanity for sheltering essential scientific potential for the improvement in the quality of living beings. It also contributes to the preservation of natural resources and the environment. Among Brazil's forest species, jenipapo (Genipa americana L.) is commonly found in riparian vegetation. The objective of this work was to quantify the genetic variability of biochemical traits of seeds, as a support for in situ and ex situ conservation of natural populations of G. americana L. Two populations of the species were studied: one from Ilha Solteira, SP region (ISA) and other from Mogi Guaçu, SP (MOG). In the ISA population, seeds were collected from 30 trees, and in the MOG population, from 22 trees. These seeds were analyzed for chemical composition: content of proteins, carbohydrates, lipids and starch. The two populations of G. americana studied had a great genetic variation for these traits. The population ISA had an additive and phenotypic correlation, which was negative and high for starch with lipid; and positive and medium, for lipid with prolamine, as well as for globulin with prolamine. The population MOG presented additive and phenotypic correlations: positive and medium for gluteline with globulin. In these populations, narrow sense heritability estimates of progenies were moderate (0.69 for carbohydrates in the population ISA) to high (0.81 to 0.99 for the other traits in the two populations), indicating that much progress can be expected with selection strategies.

Variabilidad genética y liberalización del comercio: el maíz en el Tratado de Libre Comercio de América del Norte

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La ingeniería genética y la intensificación de la agricultura argentina: algunos comentarios críticos

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