Papers by Luciana Regitano
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Journal of animal science and biotechnology, 2017
Beef cattle breeding programs in Brazil have placed greater emphasis on the genomic study of repr... more Beef cattle breeding programs in Brazil have placed greater emphasis on the genomic study of reproductive traits of males and females due to their economic importance. In this study, genome-wide associations were assessed for scrotal circumference at 210 d of age, scrotal circumference at 420 d of age, age at first calving, and age at second calving, in Canchim beef cattle. Data quality control was conducted resulting in 672,778 SNPs and 392 animals. Associated SNPs were observed for scrotal circumference at 420 d of age (435 SNPs), followed by scrotal circumference at 210 d of age (12 SNPs), age at first calving (six SNPs), and age at second calving (four SNPs). We investigated whether significant SNPs were within genic or surrounding regions. Biological processes of genes were associated with immune system, multicellular organismal process, response to stimulus, apoptotic process, cellular component organization or biogenesis, biological adhesion, and reproduction. Few association...
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BMC genomics, Jan 13, 2016
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Revista Brasileira de Zootecnia
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Archivos de Zootecnia
ABSTRACT
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Revista Brasileira de Zootecnia
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Ensembles are well-established as methods for obtaining highly accurate classifiers by combining ... more Ensembles are well-established as methods for obtaining highly accurate classifiers by combining less accurate ones [1]. An ensemble consists of a set individual predictors that are combined to improve the overall perfomance achieves. Bagging [2] and Boosting [3] are methods frequently used to assemble the ensembles. This work investigates the aplication of Bagging and Boosting, using its version AdaBoostM1 [4] to analyse molecular markers.
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Resumo: A formação da raça bovina Canchim, 5/8 Charolês + 3/8 Zebu, cuja base genética foi amplia... more Resumo: A formação da raça bovina Canchim, 5/8 Charolês + 3/8 Zebu, cuja base genética foi ampliada pelo desenvolvimento de três linhagens (antiga, nova e cruzada), buscou aproveitar o vigor híbrido e complementar a alta velocidade de crescimento e boa qualidade de carne do Charolês (Europeu) à adaptação aos trópicos do Zebu. O genótipo mitocondrial (mtDNA) é controlado por herança materna e suas variações podem levar a diferenças fenotípicas para características produtivas. No Canchim, o tipo de mtDNA (Europeu/taurus ou Zebu/indicus) não era conhecido. Neste trabalho, animais da raça Canchim do rebanho da Embrapa Pecuária Sudeste foram caracterizados por meio da genotipagem do mtDNA por PCR alelo-específico. Pela avaliação genealógica, foram determinadas as 173 matriarcas Zebus (62 Indubrasil, 3 Guzerá e 108 Nelore) formadoras da raça e seus 6.749 descendentes. Nos animais com material genético disponível (n=6.404), descendentes de 144 matriarcas, e nos animais vivos em dezembro de...
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Domestication is now appropriately viewed as a process and not an event. We use data from 134 bre... more Domestication is now appropriately viewed as a process and not an event. We use data from 134 breeds of cattle and the Illumina BovineSNP50 and BovineHD BeadChips to investigate the history of admixture and selection in cattle later in the process of domestication but prior to breed formation. From previous work, we hypothesize that the divergence of African humpless taurine cattle is due to admixture with the wild ancestor of cattle, the auroch, in Africa. We use weighted linkage disequilibrium decay curves as implemented in ALDER to further investigate this hypothesis. We also used FLK as implemented in hapFLK to investigate the history of selection. Using 780 samples from 11 breeds of cattle, signatures of selection were found ubiquitously across the genome. For the most significant departures from drift, select was inferred to occur on interior branches of the phylogeny, suggesting that selection at these loci occurred prior to geographic isolation and breed formation. These loc...
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Ars Veterinaria, 2013
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Abstract Text: Nellore beef cattle, a Bos indicus breed, is well adapted to tropical conditions a... more Abstract Text: Nellore beef cattle, a Bos indicus breed, is well adapted to tropical conditions and has allowed Brazil to become one of the world’s largest beef producers. Nevertheless, Bos indicus breeds are reported to have less tender meat than Bos taurus. A group of 138 animals was evaluated for Longissimus thoracis muscle shear force (SF). Six animals with the highest and lowest SF were then selected for protein abundance studies. Samples were subjected to two-dimensional gel electrophoresis (2-DE) to identify differentially expressed proteins associated with SF. Eight differentially expressed spots were observed (p < 0.05). These spots were submitted to a multiple regression analyses and three of them (41, 42 and 72) appeared in the best models for tenderness prediction in the three meat aging times: 24 h, 7 and 14 days. New approaches are needed to identify the protein spots and their corresponding genes. Keywords: Bos indicus, proteomics, tenderness
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Genetics and molecular research : GMR, 2014
Cytokines are small cell-signaling proteins that play an important role in the immune system, par... more Cytokines are small cell-signaling proteins that play an important role in the immune system, participating in intracellular communication. Four candidate genes of the cytokine family (IL2, IL4, IL13, and IFNG) were selected to identify Single Nucleotide Polymorphisms (SNPs) that might be associated with resistance to gastrointestinal endoparasites in goats. A population of 229 goats, F2 offspring from an F1 intercross was produced by crossing pure Saanen goats, considered as susceptible to gastrointestinal endoparasites, with pure Anglo-Nubian goats, considered resistant. Blood was collected for DNA extraction and fecal samples were also collected for parasite egg count. Polymorphisms were prospected by sequencing animals with extreme phenotype for fecal egg count (FEC) distribution. The association between SNPs and phenotype was determined by using the Fisher exact test with correction for multiple tests. Three of the 10 SNPs were identified as significant (P ≤ 0.03). They were fo...
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Developments in biologicals, 2008
Genetic differences in susceptibility to ticks (Rhipicephalus (Boophilus) microplus) are consider... more Genetic differences in susceptibility to ticks (Rhipicephalus (Boophilus) microplus) are considerable in bovines. Here, mapping, association and gene expression approaches were employed to further advance our understanding of the molecular basis of tick resistance. A B. taurus x B. indicus F2 population was developed by Embrapa and 382 individuals were measured for parasitic load. Scanning of all chromosomes is in progress. Quantitative trait loci (QTL) for tick load were mapped to chromosomes 4, 5, 7, 10, 14, 18 and 23 out of the 20 chromosomes scanned and were dependent on the season in which the phenotype was scored. In the candidate gene approach, females from the genetic groups Nelore (NE--184), Canchim x Nelore (CN--153), Aberdeen Angus x Nelore (AN--123) and Simmental x Nelore (SN--120) were evaluated under natural infestation. Microsatellite markers close to the genes for interleukin 2 (IL2), interleukin 4 (IL4) and interferon gamma (IFNG) were analysed. Tick counts were ass...
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Advances in technology and new methodologies applied to genomic evaluation are of great importanc... more Advances in technology and new methodologies applied to genomic evaluation are of great importance for improvements in the cattle industry. To begin a genomic evaluation, many factors should be taken into account; one of which is to evaluate the extent of linkage disequilibrium (LD) between genetic markers (e.g. single nucleotide polymorphism -SNP). LD is a non-random association of alleles at two or more loci in the same chromosome in which a deviation between the observed and the expected frequency exists. It results from migration, mutation, selection, and drift, or can also be created in livestock populations by crossing lines or breeds. The aim of this study was to investigate the extent of linkage disequilibrium in Canchim breed and MA genetic group using high density SNP panel. Canchim beef cattle are a synthetic breed developed at the facilities of Brazilian Agricultural Research Corporation (Embrapa). In this study we used animals from the Canchim breed (62.50% Charolais an...
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Papers by Luciana Regitano