927 resultados para Genetic Variation


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This study aimed to investigate the genetic variability of two Brazilian free range (Caipira) chickens lines using microsatellites analysis of ten loci. It was collected a total of 99 blood samples, which 49 were from Paraiso Pedres (PP) and 50 were from Rubro Negra (RN) lines. The amplification of the DNA fragments was performed by polymerase chain reaction (PCR) and the genotyping was conduct using ABI 3130 sequencer. The allele number variation was among 3 (LEI0254) to 32 (LEI0212) in the PP line, and 4 (LEI0254) to 31 (LEI0212) in the RN line. The allelic average per locus was 13.3 and 13.1 in the PP and RN lines, respectively. The average observed and the expected heterozygosity were 0.650 and 0.820 in the PP line, and 0.671 and 0.804 in the RN line. All of the analyzed loci were informative (PIC>0.5). These results indicate that these free-range animals have a high genetic variability, at least for the majority of the analyzed loci, and this genetic variation is higher than the commercial chickens and similar for the no-commercial birds.

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

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

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Prediction of genetic gains within breeding programs is not always compatible with those observed in practice. One reason for this inconsistency is the lack of knowledge of genotype-environment interaction (GxE). The aim of this study was to estimate genetic variation, evaluate the GxE, investigate the genetic correlation between pairs of environments and for the set, and to study the productivity, stability and adaptability at 2 years of age for diameter at breast height (DBH) in five progenies trials of Eucalyptus urophylla, used in a randomized complete block design, with the number of progenies ranging from 138 to 167, four to eight blocks and five to six plants per plot. Estimates of variance components and genetic parameters were obtained using the REML/BLUP method. For analysis of productivity, stability and adaptability, the HMRPGV method was used. The highest DBH growth was observed in Anhembi (10.52 cm) and Uberaba (10.20 cm). Estimates considered high were obtained for the coefficient of individual additive genetic variation (>13.3%) and average heritability among progenies (>0.40), indicating the possibility of obtaining genetic gains by selection among progenies. The coefficient of determination of the GxE was 1.7%, a fact that led to a high value of genotypic correlation between the performance of the progenies and environments (78.1%), indicating that the interaction is simple. The first six progenies showed a coincidence of 100% in the order of stability (HMGV), adaptability (RPGV) and productivity (HMRPGV), being 13% higher than the overall mean of five experiments (9.21 cm). When ordering the progenies, the selection of the 20 best in growth led to an increase in gain ranging of from 10.4 to 70%. Anhembi is the ideal place to have a breeding population which will be good in the other places as well.

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

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

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Pós-graduação em Agronomia - FEIS

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Laurencia dendroidea shows high inter- and intrapopulation variability in the amount of the sesquiterpene elatol, caused by genetic variation as well as environmental factors. To test the independent effect of physical and nutritional conditions, the growth and the levels of elatol in L. dendroidea clones were evaluated under different conditions of temperature, salinity, irradiance, and culture medium in the laboratory. Growth of L. dendroidea was clearly affected by all these factors, but elatol levels were influenced only by temperature and salinity. Better conditions for growth did not produce a similar effect on elatol production in L. dendroidea, contradicting the carbon/nutrient balance and growth/differentiation balance models. On the contrary, severe conditions of temperature and salinity promoted a decrease in elatol levels, as predicted by the environmental stress model. Our results using clones indicated that abiotic factors clearly take part in fostering chemical variations observed in natural populations, in addition to genetic factors, and can promote differential susceptibility of plant specimens to natural enemies.

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The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed.

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Objectives: This investigation was performed to examine genetic variation at the beta-globin locus in a sample of 30 healthy individuals from native populations in South America. The patterns of haplotypic variation were compared with those of previous studies including samples for various worldwide populations in an attempt to make inferences about the occupation of the Americas from a deeper temporal perspective than is typically available with haploid markers. Methods: A 2.67-kb segment containing the beta-globin gene and its flanking regions was examined for genetic variation in a sample of 60 chromosomes from native populations in South America. The fragment was PCR-amplified and directly sequenced. To determine linkage relationships in compound heterozygotes, we used the amplification refractory mutation system. In addition, we assessed genetic variability and differentiation among populations, and we performed tests of selective neutrality. These analyses were performed for Brazilian Amerindian group and other worldwide populations previously studied. Results: Eleven polymorphic sites were found in the studied fragment, which distinguished eight different haplotypes, three recombinants haplotypes (present as single copies) and five previously described haplotypes, including some of those most highly differentiated. Genetic variation found in the pooled sample is substantial. Conclusions: Although only five known haplotypes are observed in Amazonia, some of these are highly divergent, resulting in patterns of molecular polymorphism equal to or higher than those from other world regions. Am. J. Hum. Biol. 2012. (C) 2012 Wiley Periodicals, Inc.

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Characterization of population genetic variation and structure can be used as tools for research in human genetics and population isolates are of great interest. The aim of the present study was to characterize the genetic structure of Xavante Indians and compare it with other populations. The Xavante, an indigenous population living in Brazilian Central Plateau, is one of the largest native groups in Brazil. A subset of 53 unrelated subjects was selected from the initial sample of 300 Xavante Indians. Using 86,197 markers, Xavante were compared with all populations of HapMap Phase III and HGDP-CEPH projects and with a Southeast Brazilian population sample to establish its population structure. Principal Components Analysis showed that the Xavante Indians are concentrated in the Amerindian axis near other populations of known Amerindian ancestry such as Karitiana, Pima, Surui and Maya and a low degree of genetic admixture was observed. This is consistent with the historical records of bottlenecks experience and cultural isolation. By calculating pair-wise F-st statistics we characterized the genetic differentiation between Xavante Indians and representative populations of the HapMap and from HGDP-CEPH project. We found that the genetic differentiation between Xavante Indians and populations of Ameridian, Asian, European, and African ancestry increased progressively. Our results indicate that the Xavante is a population that remained genetically isolated over the past decades and can offer advantages for genome-wide mapping studies of inherited disorders.