Assinaturas de seleção em bovinos da raça Canchim
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Data
2014-07-18
Autores
Urbinati, Ismael [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Recentes avanços tecnológicos em genética permitiram a genotipagem de espécies de interesse zootécnico, como os bovinos. Foram desenvolvidos painéis de genotipagem com diferentes densidades de marcadores do tipo polimorfismos de nucleotídeo único (“single nucleotide polymorphism” - SNP). Painéis de alta densidade permitiram maior cobertura do genoma e possibilitaram sua aplicação em diferentes tipos de estudos, como a identificação de regiões do genoma conservadas devido à seleção. Tais regiões são denominadas assinaturas de seleção (AS). As AS são detectáveis por diferentes metodologias, como a Homozigose do Haplótipo Estendido (“extended haplotype homozygosity” – EHH) e o Escore de Integração dos Haplótipos (“integrated haplotype score” - iHS), sendo esta última derivada da EHH. O objetivo desse trabalho foi identificar regiões de AS em bovinos de corte da raça Canchim, genotipados com painel de alta densidade, visando futuras aplicações no melhoramento genético animal. O pacote rehh do programa R foi utilizado para identificação de AS por meio da metodologia iHS. Foram utilizados registros de 285 animais da raça Canchim, 114 do grupo genético MA e um da raça Charolês. Todos os animais (amostras) foram genotipados com o painel Illumina BovineHD BeadChip (786.799 SNPs) e provenientes da base de dados da Embrapa Pecuária Sudeste, São Carlos, SP. O controle de qualidade de genótipos (CQ) foi realizado por meio do pacote snpStats, do R. Após o CQ, restaram 687.655 marcadores SNP e 396 amostras. Foi utilizado o programa BEAGLE para a inferência das fases de ligação e construção dos haplótipos, etapa necessária para utilização da iHS. A estatística iHS para cada um dos marcadores foi transformada em para conveniência da análise dos resultados. Valores de foram observados nos cromossomos BTA (Bos taurus) 5 e 14, com 39 e nove SNPs estatisticamente significativos ...
Genomic selection has been considered as a technique that will allow significant increase in the genetic progress of animal breeding programs. Recent technological advances in genetics have allowed the genotyping of livestock species such as cattle, by means of single nucleotide polymorphism (SNP) chip panels. High-density SNP panels have allowed greater coverage of the genome and its application in different studies, such as the identification of conserved regions of the genome due to selection. Such regions are known as selection signatures (SS). The SS are detectable by various methods, such as the extended haplotype homozygosity (EHH); and the integrated haplotype score (iHS), which is derived from the HHE. The aim of this study was to identify regions of SS in Canchim beef cattle, genotyped with high-density SNP panel, and evaluate its future application in animal breeding. The rehh package of the R software was used for identification of SS through the iHS methodology. Data on 285 Canchim animals, 114 “MA” genetic group (cross between Charolais sires and Canchim-zebu dams), and one Charolais breed individual were used. The database used in this study was provided by Embrapa Cattle Southeast (São Carlos, SP, Brazil), which contains animals (samples) genotyped with the Illumina BovineHD BeadChip panel (786,799 SNPs). The quality control of genotypes (QC) was performed through snpStats package present in R. After the QC, a total of 687,655 SNP markers and 396 samples remained for SS analysis. The BEAGLE software was used to infer the linkage phase and to construct the haplotypes. The iHS statistic for each marker was transformed into piHS for better understanding of the results. On the Bos taurus (BTA) chromosomes 5 and 14 were observed piHS ? 5 (P <0.00001), with 39 and nine statistically significant SNPs, respectively. Windows of one million base pairs each were built to assist in the delimitation of SS regions. Within ...
Genomic selection has been considered as a technique that will allow significant increase in the genetic progress of animal breeding programs. Recent technological advances in genetics have allowed the genotyping of livestock species such as cattle, by means of single nucleotide polymorphism (SNP) chip panels. High-density SNP panels have allowed greater coverage of the genome and its application in different studies, such as the identification of conserved regions of the genome due to selection. Such regions are known as selection signatures (SS). The SS are detectable by various methods, such as the extended haplotype homozygosity (EHH); and the integrated haplotype score (iHS), which is derived from the HHE. The aim of this study was to identify regions of SS in Canchim beef cattle, genotyped with high-density SNP panel, and evaluate its future application in animal breeding. The rehh package of the R software was used for identification of SS through the iHS methodology. Data on 285 Canchim animals, 114 “MA” genetic group (cross between Charolais sires and Canchim-zebu dams), and one Charolais breed individual were used. The database used in this study was provided by Embrapa Cattle Southeast (São Carlos, SP, Brazil), which contains animals (samples) genotyped with the Illumina BovineHD BeadChip panel (786,799 SNPs). The quality control of genotypes (QC) was performed through snpStats package present in R. After the QC, a total of 687,655 SNP markers and 396 samples remained for SS analysis. The BEAGLE software was used to infer the linkage phase and to construct the haplotypes. The iHS statistic for each marker was transformed into piHS for better understanding of the results. On the Bos taurus (BTA) chromosomes 5 and 14 were observed piHS ? 5 (P <0.00001), with 39 and nine statistically significant SNPs, respectively. Windows of one million base pairs each were built to assist in the delimitation of SS regions. Within ...
Descrição
Palavras-chave
Bovino de corte, Canchim (Bovino), Genomas, Genetica animal, Marcadores biologicos, Animal genetics
Como citar
URBINATI, Ismael. Assinaturas de seleção em bovinos da raça Canchim. 2014. iii, 65 p. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agrárias e Veterinárias, 2014.