Consulta: creatorFacets:"Machado,Marco Antonio"
Registros recuperados: 8
Data/hora: 10/06/2024 12:02:10

Association of the bovine major histocompatibility complex (BoLA) BoLA-DRB3 gene with fat and protein production and somatic cell score in Brazilian Gyr dairy cattle (Bos indicus)
Provedor de dados: Genetics and Molecular Biology
Autores: Nascimento,Carlos Souza do; Machado,Marco Antonio; Martinez,Mario Luiz; Silva,Marcos Vinícius G. Barbosa da; Guimarães,Marta Fonseca Martins; Campos,Ana Lúcia; Azevedo,Ana Luisa Sousa; Teodoro,Roberto Luiz; Verneque,Rui da Silva; Guimarães,Simone Eliza Facioni; Oliveira,Denise Aparecida Andrade.
The effect of the bovine major histocompatibility complex (BoLA) locus on animal health may be due to a direct action of its alleles on immune functions, whereas its indirect effect on production traits might be explained by the better general health conditions of more productive animals. In the present study, the BoLA-DRB3 gene was investigated in 1058 cows belonging to seven Brazilian Gyr Dairy herds (Bos indicus, Zebu cattle). A total of 37 alleles were identified, 15 of them described for the first time in a Zebu breed. A highly significant association (p &lt; 0.02) was observed between allele *54 and a decrease (-26.1 kg) in milk protein yield and there was a significant association (p &lt; 0.05) between this allele and lower (-26.07 kg) milk fat...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cattle; Marker-assisted selection; Molecular markers; PCR-RFLP.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000400011

Zero-inflated Poisson regression models for QTL mapping applied to tick-resistance in a Gyr x Holstein F2 population
Provedor de dados: Genetics and Molecular Biology
Autores: Silva,Fabyano Fonseca; Tunin,Karen P.; Rosa,Guilherme J.M.; Silva,Marcos V.B. da; Azevedo,Ana Luisa Souza; Verneque,Rui da Silva; Machado,Marco Antonio; Packer,Irineu Umberto.
Nowadays, an important and interesting alternative in the control of tick-infestation in cattle is to select resistant animals, and identify the respective quantitative trait loci (QTLs) and DNA markers, for posterior use in breeding programs. The number of ticks/animal is characterized as a discrete-counting trait, which could potentially follow Poisson distribution. However, in the case of an excess of zeros, due to the occurrence of several noninfected animals, zero-inflated Poisson and generalized zero-inflated distribution (GZIP) may provide a better description of the data. Thus, the objective here was to compare through simulation, Poisson and ZIP models (simple and generalized) with classical approaches, for QTL mapping with counting phenotypes...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dairy; Cattle; Tick infestation; QTL regression; Generalized linear model.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000400008

Quantitative trait loci (QTL) mapping for growth traits on bovine chromosome 14
Provedor de dados: Genetics and Molecular Biology
Autores: Miyata,Marcelo; Gasparin,Gustavo; Coutinho,Luiz Lehmann; Martinez,Mario Luiz; Machado,Marco Antonio; Silva,Marcos Vinicius G. Barbosa da; Campos,Ana Lucia; Sonstegard,Tad S.; Rosário,Millor Fernandes do; Regitano,Luciana Correia de Almeida.
Quantitative trait loci (QTL) mapping in livestock allows the identification of genes that determine the genetic variation affecting traits of economic interest. We analyzed the birth weight and weight at 60 days QTL segregating on bovine chromosome BTA14 in a F2 resource population using genotypes produced from seven microsatellite markers. Phenotypes were derived from 346 F2 progeny produced from crossing Bos indicus Gyr x Holstein Bos taurus F1 parents. Interval analysis to detect QTL for birth weight revealed the presence of a QTL (p &lt; 0.05) at 1 centimorgan (cM) from the centromere with an additive effect of 1.210 ± 0.438 kg. Interval analysis for weight at 60 days revealed the presence of a QTL (p &lt; 0.05) at 0 cM from the centromere with an...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: TA14; Cattle; F2; Growth traits; Molecular markers; QTL.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000300011

Genes do eixo somatotrófico e características de crescimento numa população F2 de bovinos
Provedor de dados: Pesquisa Agropecuária Brasileira
Autores: Silva,Marcos Vinicius Gualberto Barbosa da; Martinez,Mário Luiz; Machado,Marco Antonio; Nascimento,Carlos Souza do; Campos,Ana Lúcia; Guimarães,Marta Fonseca Martins; Azevedo,Ana Luisa Sousa; Moita,Antônia Kécya França; Lui,Jeffrey Frederico.
O objetivo deste trabalho foi avaliar a associação dos polimorfismos dos genes bGH, IGF-1 e PIT-1 com características de peso e ganho de peso numa população F2 de bovinos (Gir x Holandês), pela técnica de PCR-RFLP. As freqüências alélicas A e B, do gene PIT-1, e dos genótipos AA, AB e BB, nas populações parentais foram semelhantes entre si, mas diferentes das freqüências nas populações cruzadas F1 e F2, para esse gene. Quanto ao gene bGH, os animais da raça Holandesa apresentaram freqüência de 100% para o alelo E e os animais da raça Gir, 92% para o alelo F, resultando em alta freqüência de indivíduos heterozigotos nas populações F1 e F2. Quanto ao gene IGF-1, todos os animais da raça Holandesa eram heterozigotos (AB) e, nos animais Gir, a maioria dos...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Marcadores moleculares; PCR-RFLP.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2006000600013

Relative expression of mRNAs related to cavitation process in bovine embryos produced in vivo and in vitro
Provedor de dados: Revista Brasileira de Zootecnia
Autores: Wohlres-Viana,Sabine; Boite,Mariana Cortes; Viana,João Henrique Moreira; Machado,Marco Antonio; Camargo,Luiz Sérgio de Almeida.
The objectives of this work were to identify and to evaluate possible differences on gene expression of aquaporins and Na/K-ATPases transcripts between embryos in vivo and in vitro produced. For each group, 15 blastocysts distributed in three pools were used for RNA extraction followed by amplification and reverse transcription. The resulting cDNAs were submitted to Real-Time PCR, using the GAPDH gene as endogenous control. It was not possible to identify AQP1 transcripts. Relative expression of AQP3 (1.33 ± 0.78) and AQP11 (2.00 ± 1.42) were not different in blastocysts in vitro and in vivo produced. Na/K-ATPase α1 gene (2.25 ± 1.07) was overregulated whereas Na/K-ATPase β2 transcripts 0.40 ± 0.30) did not differ among blastocysts produced in vitro from...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Blastocoel; Gene expression; Osmotic gradient; Water channel.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982011000100017

Genetic diversity of four cattle breeds using microsatellite markers
Provedor de dados: Revista Brasileira de Zootecnia
Autores: Machado,Marco Antonio; Schuster,Ivan; Martinez,Mário Luiz; Campos,Ana Lúcia.
Four cattle breeds (Gyr, Nellore, Guzerat and Holstein) were analyzed by amplification of genomic DNA using microsatellite loci to evaluate the genetic diversity within and among them. DNA samples of 18 animals from each breed were collected to access the genetic content of them. Allele frequencies were calculated and used to generate a Nei's genetic distance matrix what was used to build a dendrogram following UPGMA clustering. As expected, Holstein breed was the most distinct from the other breeds: 1.15 in relation to Gyr, 1.12 in relation to Nellore and 0.94 in relation to Guzerat. The closest genetic distance was 0.25 between Guzerat and Nellore. A total of 64 alleles in all four breeds were detected using nine microsatellite primers. Each breed showed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bovine; DNA; Genetic diversity; Marker; Microsatellite.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982003000100012

Diversidade genética entre acessos de capim-elefante obtida com marcadores moleculares
Provedor de dados: Revista Brasileira de Zootecnia
Autores: Pereira,Antonio Vander; Machado,Marco Antonio; Azevedo,Ana Luisa Sousa; Nascimento,Carlos Souza do; Campos,Ana Lúcia; Lédo,Francisco José da Silva.
Este trabalho foi realizado para estimar a diversidade genética de 30 acessos de capim-elefante utilizando-se marcadores moleculares. Amostras de DNA genômico de cada acesso foram obtidas para realização da amplificação por PCR utilizando a técnica de marcadores RAPD. Foram utilizados 20 primers aleatórios que geraram 88 bandas de DNA de alta intensidade e reprodutíveis (64 bandas polimórficas e 24 monomórficas). Os acessos foram agrupados pelo método UPGMA com base na estimativa das distâncias genéticas. Os grupos de acessos Porto Rico, Santa Rita e IJ-7136 cv. EMPASC 307 e; Mineiro e Mineiro Ipeaco apresentaram distância genética nula entre si, comprovando tratar-se do mesmo material genético com designação diferente. Alguns pares de acessos apresentaram...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Marcadores moleculares; Pennisetum purpureum; RAPD; Variabilidade genética.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982008000700011

Molecular characterization of elephantgrass accessions through RAPD markers
Provedor de dados: Ciência e Agrotecnologia
Autores: Passos,Leônidas Paixão; Machado,Marco Antonio; Vidigal,Maria Coletta; Campos,Ana Lúcia.
Elephantgrass pastures are limited by yield variations and reductions in forage quality and availability, thus making the search for genotypes with reduced seasonality a major concern. In order to verify the extent of genetic variability among contrasting cultivars, ten elephantgrass accessions were analyzed through DNA amplification by RAPD technique. A total of 160 DNA bands were generated with the use of 44 random primers and 23% of these bands were monomorphic for all accessions. Gel-obtained binary data (1 for presence and 0 for absence) were used for generating a genetic distance matrix, which was utilized in a UPGMA grouping analysis. Elephantgrass cultivars Cameroon and Vruckwona were the accessions mostly divergent from the others, with an average...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Molecular markers; Elephantgrass; RAPD; DNA.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542005000300009