Estudo genômico de características de desempenho reprodutivo em bovinos da raça Nelore
Carregando...
Data
2020-06-19
Autores
Sbardella, Ana Paula [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A informação genômica vem sendo aplicada como importante ferramenta em programas de melhoramento animal. Desta maneira, pode contribuir para melhorar o desempenho reprodutivo dos animais visando atender à crescente demanda por carne bovina. Este trabalho tem como objetivos: (1) Identificar a associação entre polimorfismos de nucleotídeo único (SNP) com as características de circunferência escrotal aos 365 dias de idade (CE365) e aos 450 dias de idade (CE450), período de gestação (PG), como característica do bezerro, idade ao primeiro parto (IPP), produtividade acumulada (PAC), parto precoce até 30 meses de idade (P30) e habilidade de permanência da vaca no rebanho (“Stayability” - STAY) a fim de detectar genes candidatos e vias biológicas associadas com características reprodutivas em bovinos de corte da raça Nelore; (2) Comparar a acurácia de predição de características reprodutivas usando os métodos Melhor preditor linear não-viesado (BLUP) e Melhor preditor linear não viesado genômico de único passo (ssGBLUP) e classificar cada animal segundo seu valor genético (EBV) e valor genético genômico (GEBV), estimados para as características estudadas, visando obter informações mais acuradas para a seleção de animais jovens; (3) Comparar grupos de animais para as características estudadas, resultantes de análises de agrupamento com as estimativas de EBV e GEBV, afim de identificar aqueles que apresentam melhor potencial genético para o desempenho reprodutivo. Para isso, foram utilizados dados fenotípicos, de pedigree e genotípicos disponibilizados pela Associação Nacional de Criadores e Pesquisadores (ANCP). Os dados genotípicos são oriundos de 8.652 animais, genotipados ou imputados para painéis de marcadores SNP em alta densidade (Illumina Bovine HD BeadChip). Dados fenotípicos de 50.331 e 34.848 animais foram utilizados para estudo de associação genômica ampla (GWAS) e seleção genômica (GS), respectivamente. O GWAS em passo único ponderado (WssGWAS) foi utilizado para estimação dos efeitos dos SNP sobre as características estudadas. Para comparar a habilidade de predição foram utilizados os métodos de avaliação BLUP e ssGBLUP. Em seguida, as análises de agrupamento hierárquica e não hierárquica foram realizadas para agrupar os animais com base no EBV ou GEBV. Os resultados do presente estudo revelaram genes com importantes funções para características reprodutivas, como os influenciadores na fertilidade e precocidade. Os genes CAMK1D, ACOXL, MRPL33, PLCB1 e JAG1, entre outros, aparecem associados com mais de uma característica. Os resultados de habilidade de predição resultantes do método ssGBLUP (0,07 - 0,46), em sua maioria foram maiores do que os resultados obtidos pelo método BLUP (0,06 - 0,41). Ademais, uma diferença nos valores genéticos dos animais quando a informação genômica é incorporada nas análises foi observada, o que pode contribuir no direcionamento da seleção de animais jovens segundo o GEBV. O GWAS evidenciou que a identificação de regiões associadas com as características estudadas pode contribuir com futuros estudos de validação biológica e os genes identificados serem indicados como candidatos a seleção. Ainda, os resultados de GS indicaram que a inclusão da informação genômica melhora a habilidade de predição de características reprodutivas e que a seleção de animais superiores para as características de interesse pode ser diferente quando a informação genômica é considerada.
Genomic information has been applied as important tool in animal breeding programs. In this way, it can contribute to improving the reproductive performance of the animals in order to meet the growing demand for beef. The aim of this study was: (1) to identify the association between single nucleotide polymorphisms (SNP) with scrotal circumference at 365 days (SC365) and at 450 days (SC450), gestation length (GL) as a calf trait, age at first calving (AFC), accumulated productivity (ACP), heifer early calving until 30 months (HC30) and Stayability (STAY) traits, in order to detect candidate genes and biological pathways associated with reproductive traits in Nelore beef cattle; (2) To compare predictive accuracy of reproductive traits using the Best Linear Unbiased Prediction (BLUP) and the Single-step Genomic BLUP (ssGBLUP) methods and to order each animal according to their breeding value (EBV) and genomic breeding value (GEBV), estimated for the traits studied aiming to obtain more accurate information for young animals selection; (3) To compare clusters of the animals for the evaluated traits, resulting from cluster analyzes with EBV and GEBV, in order to identify those who have the best genetic potential for reproductive performance. The data set was composed of pedigree, phenotypes and genotypes of Nelore beef cattle, from the "Associação Nacional de Criadores e Pesquisadores" (ANCP). Genotyped data in HD or imputed to high density SNP marker panels are from 8,652 animals (males and females). The phenotype data from 50.331 e 34.848 animals were used for genome-wide association study (GWAS) and genome selection (GS), respectively. The weighted genomic single step (WssGWAS) was used to estimate the effects of SNP on the studied traits. To estimate the ability prediction, the BLUP and ssGBLUP evaluation methods were used. Then, the hierarchical and non-hierarchical cluster analyzes were performed to group the animals based on EBV or GEBV. The results obtained in this study revealed genes with important functions for reproductive traits, such as those influencing fertility and precocity. The CAMK1D, ACOXL, MRPL33, PLCB1 and JAG1 genes, among others, appear to be associated with more than one trait. The prediction ability results from ssGBLUP method (0.07 to 0.46) was higher them BLUP method (0.06 to 0.41). In addition, a difference in the genetic values of animals when genomic information is incorporated into the analyzes was observed, which can contribute to directing the selection of young animals according to the GEBV. The identification of regions associated with the studied traits can contribute to future studies of biological validation and the identified genes are indicated as candidates for selection. Also, the inclusion of genomic information improves the ability to predict reproductive traits. These results indicate that the selection of superior animals for the traits of interest may be different when the genomic information is considered.
Genomic information has been applied as important tool in animal breeding programs. In this way, it can contribute to improving the reproductive performance of the animals in order to meet the growing demand for beef. The aim of this study was: (1) to identify the association between single nucleotide polymorphisms (SNP) with scrotal circumference at 365 days (SC365) and at 450 days (SC450), gestation length (GL) as a calf trait, age at first calving (AFC), accumulated productivity (ACP), heifer early calving until 30 months (HC30) and Stayability (STAY) traits, in order to detect candidate genes and biological pathways associated with reproductive traits in Nelore beef cattle; (2) To compare predictive accuracy of reproductive traits using the Best Linear Unbiased Prediction (BLUP) and the Single-step Genomic BLUP (ssGBLUP) methods and to order each animal according to their breeding value (EBV) and genomic breeding value (GEBV), estimated for the traits studied aiming to obtain more accurate information for young animals selection; (3) To compare clusters of the animals for the evaluated traits, resulting from cluster analyzes with EBV and GEBV, in order to identify those who have the best genetic potential for reproductive performance. The data set was composed of pedigree, phenotypes and genotypes of Nelore beef cattle, from the "Associação Nacional de Criadores e Pesquisadores" (ANCP). Genotyped data in HD or imputed to high density SNP marker panels are from 8,652 animals (males and females). The phenotype data from 50.331 e 34.848 animals were used for genome-wide association study (GWAS) and genome selection (GS), respectively. The weighted genomic single step (WssGWAS) was used to estimate the effects of SNP on the studied traits. To estimate the ability prediction, the BLUP and ssGBLUP evaluation methods were used. Then, the hierarchical and non-hierarchical cluster analyzes were performed to group the animals based on EBV or GEBV. The results obtained in this study revealed genes with important functions for reproductive traits, such as those influencing fertility and precocity. The CAMK1D, ACOXL, MRPL33, PLCB1 and JAG1 genes, among others, appear to be associated with more than one trait. The prediction ability results from ssGBLUP method (0.07 to 0.46) was higher them BLUP method (0.06 to 0.41). In addition, a difference in the genetic values of animals when genomic information is incorporated into the analyzes was observed, which can contribute to directing the selection of young animals according to the GEBV. The identification of regions associated with the studied traits can contribute to future studies of biological validation and the identified genes are indicated as candidates for selection. Also, the inclusion of genomic information improves the ability to predict reproductive traits. These results indicate that the selection of superior animals for the traits of interest may be different when the genomic information is considered.
Descrição
Palavras-chave
Bos taurus indicus, Características reprodutivas, Associação ampla do genoma, Seleção genômica, Reproduction traits, Genome-wide association, Genomic selection