939 resultados para correlated mating


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Data comprising 53,181 calving records were analyzed to estimate the genetic correlation between days to calving (DC), and days to first calving (DFC), and the following traits: scrotal circumference (SC), age at first calving (AFC), and weight adjusted for 550 d of age (W550) in a Nelore herd. (Co)variance components were estimated using the REML method fitting bivariate animal models. The fixed effects considered for DC were contemporary group, month of last calving, and age at breeding season (linear and quadratic effects). Contemporary groups were composed by herd, year, season, and management group at birth; herd and management group at weaning; herd, season, and management group at mating; and sex of calf and mating type (multiple sires, single sire, or AI). In DFC analysis, the same fixed effects were considered excluding the month of last calving. For DC, a repeatability animal model was applied. Noncalvers were not considered in analyses because an attempt to include them, attributing a penalty, did not improve the identification of genetic differences between animals. Heritability estimates ranged from 0.04 to 0.06 for DC, from 0.06 to 0.13 for DFC, from 0.42 to 0.44 for SC, from 0.06 to 0.08 for AFC, and was 0.30 for W550. The genetic correlation estimated between DC and SC was low and negative (-0.10), between DC and AFC was high and positive (0.76), and between DC and W550 was almost null (0.07). Similar results were found for genetic correlation estimates between DFC and SC (-0.14), AFC (0.94), and W550 (-0.02). The genetic correlation estimates indicate that the use of DC in the selection of beef cattle may promote favorable correlated responses to age at first mating and, consequently, higher gains in sexual precocity can be expected.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Six microsatellite loci were used to quantify the mating system of two small fragmented populations (Selviria - SEL and Aparecida do Tabuado APT, Mato Grosso do Sul State) and isolated trees in pastures, of the bat-pollinated tropical tree Hymenaea stignocarpa, growing in the Center-west region of Brazil. In SEL population, seeds were collected from 11 mother-trees; in APT, from three trees and, in the case of isolated trees, from six individuals growing at least 500 m apart in pastures. To investigate if there are differences on mating system between trees in populations and isolated trees, trees from populations were pooled as a group and, likewise, the isolated trees were pooled to another group. The outcrossing rate was higher in the populations ((t) over cap (m)=0.873) than in isolated trees ((t) over cap (m)=0.857), but the difference was not significant. Significant and high differences between multi-locus and single-locus outcrossing rate were detected in populations ((t) over cap (m)-(t) over cap (s)=0.301, P<0.05) and isolated trees (<(t)over cap>(m)-(t) over cap (s) = 0.276, P < 0.05), suggesting mating between relatives. Higher paternity correlation was observed in trees from population (<(r)over cap>(p)=0.636) than in isolated trees ((r) over cap (p)=0.377), indicating the occurrence of some correlated matings and that part of offspring are full-sibs. It was not observed increased in self-fertilization rate in isolated trees in pastures. In general terms, the unique observed difference in mating system between populations and isolate trees was the high rate of correlated matings in trees from populations, due probably to the small distance among coespecifics and the pollinator behavior, visiting near trees.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Macrophage activity, cytokines serum concentration, serum neutralizing antibodies and lethality by rabies were evaluated in swiss mice experimentally infected with street rabies virus and submitted or not to antirabies vaccination and immunomodulation with P. acnes. Animals were killed at different times and serum was collected in order to evaluate cytokines concentration; peritonial and splenic macrophages were collected for macrophage activity evaluation. Greater survival rates higher IL-10 and low IL-6 serum concentration were observed in vaccinated animals treated using P. acnes. (C) 2004 Elsevier Ltd. All rights reserved.

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Purpose: Genetic biomarkers of head and neck tumors could be useful for distinguishing among patients with similar clinical and histopathologic characteristics but having differential probabilities of survival. The purpose of this study was to investigate chromosomal alterations in head and neck carcinomas and to correlate the results with clinical and epidentiologic variables.Experimental Design: Cytogenetic analysis of short-term cultures from 64 primary untreated head and neck squamous cell carcinomas was used to determine the overall pattern of chromosome aberrations. A representative subset of tumors was analyzed in detail by spectral karyotyping and/or confirmatory fluorescence in situ hybridization analysis.Results: Recurrent losses of chromosomes Y (26 cases) and 19 (14 cases), and gains of chromosomes 22 (23 cases), 8 and 20 (11 cases each) were observed. The most frequent structural aberration was del(22)(q13.1) followed by rearrangements involving 6q and 12p. The presence of specific cytogenetic aberrations was found to correlate significantly with an unfavorable outcome. There was a significant association between survival and gains in chromosomes 10 (P = 0.008) and 20 (P = 0.002) and losses of chromosomes 15 (P = 0.005) and 22 (P = 0.021). Univariate analysis indicated that acquisition of monosomy 17 was a significant (P = 0.0012) factor for patients with a previous family history of cancer.Conclusions: the significant associations found in this study emphasize that alterations of distinct regions of the genome may be genetic biomarkers for a poor prognosis. Losses of chromosomes 17 and 22 can be associated with a family history of cancer.

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Descrevemos o comportamento reprodutivo de Adelosgryllus rubricephalus Mesa & Zefa, 2004. em observações realizadas em laboratório verificamos a seguinte seqüência no comportamento de acasalamento: (1) reconhecimento sexual por antenação; (2) corte, em que o macho volta seu abdômen em direção à fêmea, vibra as antenas médio-lateralmente, treme o corpo ântero-posteriormente e estridula intermitentemente, enquanto a fêmea receptiva toca a ponta do abdômen, os cercos e os fêmures posteriores do macho, com seus palpos ou tarsos anteriores; o macho então fica imóvel por alguns segundos, expõe o espermatóforo e ambos retomam a seqüência comportamental descrita acima; (3) cópula: o macho coloca-se sob a fêmea, com suas tégminas inclinadas para frente, anexa sua genitália à dela e promove a transferência do esperma; a fêmea desce de cima do macho e ocorre brevemente a posição end-to-end durante a separação do casal; (4) pós-cópula: não há comportamento de guarda; o macho retém o espermatóforo e o ingere. Quantificamos o intervalo de tempo das principais etapas do acasalamento e discutimos suas possíveis implicações no comportamento observado.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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