Navegando por Autor "Silva, Marcos Vinicius Gualberto Barbosa da"
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Item Embryo biopsies for genomic selection in tropical dairy cattle(2023) Oliveira, Clara Slade; Camargo, Luiz Sergio Almeida; Silva, Marcos Vinicius Gualberto Barbosa da; Saraiva, Naiara Zoccal; Quintão, Carolina Capobiango; Machado, Marco AntonioAbstract Genomic selection has transformed the livestock industry, enabling early-life selection of animals. Biopsy sampling of pre-implantation embryos has been described since 1968. However, it was only after 2010, with the advancement of molecular biology techniques such as whole genomic amplification and SNP Chips, that next-generation sequencing became commercially available for bovine embryos. It is now possible to make decisions about which embryos to transfer not only based on recipients’ availability or embryo morphology but also on genomic estimates. This technology can be implemented for a wide spectrum of applications in livestock. In this review, we discuss the use of embryo biopsy for genomic selection and share our experience with Gir and Girolando Brazilian breeding programs, as well as future goals for implementing it in Brazilian bovine in vitro embryo production practices.Item Embryo biopsies for genomic selection in tropical dairy cattle(2023) Oliveira, Clara Slade; Camargo, Luiz Sergio Almeida; Silva, Marcos Vinicius Gualberto Barbosa da; Saraiva, Naiara Zoccal; Quintão, Carolina Capobiango; Machado, Marco AntonioAbstract Genomic selection has transformed the livestock industry, enabling early-life selection of animals. Biopsy sampling of pre-implantation embryos has been described since 1968. However, it was only after 2010, with the advancement of molecular biology techniques such as whole genomic amplification and SNP Chips, that next-generation sequencing became commercially available for bovine embryos. It is now possible to make decisions about which embryos to transfer not only based on recipients’ availability or embryo morphology but also on genomic estimates. This technology can be implemented for a wide spectrum of applications in livestock. In this review, we discuss the use of embryo biopsy for genomic selection and share our experience with Gir and Girolando Brazilian breeding programs, as well as future goals for implementing it in Brazilian bovine in vitro embryo production practices.Item Estrutura populacional da raça Girolando(2014) Canaza-Cayo, Ali William; Lopes, Paulo Sávio; Silva, Marcos Vinicius Gualberto Barbosa da; Cobuci, Jaime Araújo; Torres, Robledo de Almeida; Martins, Marta Fonseca; Arbex, Wagner AntonioThe aim of this study was to evaluate the population structure of Girolando cattle in Brazil. The pedigree file contained 26,969 individuals, from which 3,031 were males and 23,938 were females. The average level of completeness of the pedigree in the current generation was of reasonable quality (61%). Inbreeding and average relatedness coefficients were low: 0.11 and 0.13%, respectively. Estimates of effective population size considering the full generations traced was 188, which is above the critical level range. The number of ancestors that contributed to the reference population was 9,457 animals, from which 457 explained 50% of the genetic variability of the population. The effective number of founders and the effective number of ancestors in this population were, respectively, 551 and 393. The average generation interval was 5.26 years, slightly higher in genetic pathways dam-son and sire-daughter. The inbreeding in the Girolando breed was of small magnitude, indicating that the current practices of mating were adequate during the study period. However, it is important to continue monitoring these coefficients in order to prevent loss of genetic variability O objetivo neste estudo foi avaliar a estrutura genética da população de bovinos da raça Girolando no Brasil. Analisou-se o arquivo de pedigree de 26.969 animais, composto de 3.031 machos e 23.938 fêmeas. O nível de conteúdo de informação do pedigree na geração atual foi 61%, mostrando ser de qualidade moderada. O coeficiente de endogamia médio e o coeficiente de relação médio da população Girolando foram 0,11 e 0,13%, respectivamente. O tamanho efetivo da população, considerando a geração completa traçada, foi 188, acima do nível crítico. Do total de 9.457 ancestrais que contribuíram para a população de referência, 457 explicaram 50% da variabilidade genética da população. O número efetivo de fundadores foi 551 e o de ancestrais 393. O intervalo médio de geração foi de 5,26 anos, sendo ligeiramente maior nas trilhas gaméticas mãe-filho e pai-filha. A partir dos coeficientes estimados, pode-se concluir que a endogamia nos rebanhos da raça Girolando foi de pequena magnitude e que as práticas de acasalamento foram adequadas durante o período avaliado. No entanto, é importante continuar com o monitoramento desses coeficientes a fim de prevenir perda de variabilidade genéticaItem Genomic selection in multi-breed dairy cattle populations(2016) Cole, John Bruce; Silva, Marcos Vinicius Gualberto Barbosa daABSTRACT Genomic selection has been a valuable tool for increasing the rate of genetic improvement in purebred dairy cattle populations. However, there also are many large populations of crossbred dairy cattle in the world, and multi-breed genomic evaluations may be a valuable tool for improving rates of genetic gain in those populations. Multi-breed models are an extension of single-breed genomic models in which a genomic relationship matrix is used to account for the breed origin of alleles in the population, as well as allele frequency differences between breeds. Most studies have found little benefit from multi-breed evaluations for pure breeds that have large reference populations. However, breeds with small reference populations may benefit from inclusion in a multi-breed evaluation without adversely affecting evaluations for purebred performance. Most research has been conducted in taurine breeds, so additional research is needed to determine the value of multi-breed reference populations for composite and synthetic breeds that include both indicine and taurine cattle adapted to tropical climates.Item Genomic selection in multi-breed dairy cattle populations(2016) Cole, John Bruce; Silva, Marcos Vinicius Gualberto Barbosa daABSTRACT Genomic selection has been a valuable tool for increasing the rate of genetic improvement in purebred dairy cattle populations. However, there also are many large populations of crossbred dairy cattle in the world, and multi-breed genomic evaluations may be a valuable tool for improving rates of genetic gain in those populations. Multi-breed models are an extension of single-breed genomic models in which a genomic relationship matrix is used to account for the breed origin of alleles in the population, as well as allele frequency differences between breeds. Most studies have found little benefit from multi-breed evaluations for pure breeds that have large reference populations. However, breeds with small reference populations may benefit from inclusion in a multi-breed evaluation without adversely affecting evaluations for purebred performance. Most research has been conducted in taurine breeds, so additional research is needed to determine the value of multi-breed reference populations for composite and synthetic breeds that include both indicine and taurine cattle adapted to tropical climates.Item Identification of selection signatures in livestock species(2014) Gouveia, João José de Simoni; Silva, Marcos Vinicius Gualberto Barbosa da; Paiva, Samuel Rezende; Oliveira, Sônia Maria Pinheiro deThe identification of regions that have undergone selection is one of the principal goals of theoretical and applied evolutionary genetics. Such studies can also provide information about the evolutionary processes involved in shaping genomes, as well as physical and functional information about genes/genomic regions. Domestication followed by breed formation and selection schemes has allowed the formation of very diverse livestock breeds adapted to a wide variety of environments and with special characteristics. The advances in genomics in the last five years have enabled the development of several methods to detect selection signatures and have resulted in the publication of a considerable number of studies involving livestock species. The aims of this review are to describe the principal effects of natural/artificial selection on livestock genomes, to present the main methods used to detect selection signatures and to discuss some recent results in this area. This review should be useful also to research scientists working with wild animals/non-domesticated species and plant biologists working with breeding and evolutionary biology.