Polimorfismos em genes associados à puberdade e ocorrência de prenhez precoce em bovinos de corte
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Data
2016-07-27
Autores
Dias, Marina Mortati
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Universidade Estadual Paulista (Unesp)
Resumo
Características reprodutivas, como a idade à puberdade, são economicamente relevantes para sistemas de produção de carne. A ocorrência de prenhez precoce aos 16 meses (OPP) é considerada um indicador da idade à puberdade e pode ser utilizada como critério de seleção. A busca por mutações potencialmente causais em genes candidatos pode ajudar a melhorar a acurácia de predição genômica se forem inseridas em painéis de marcadores genéticos. O objetivo desse estudo foi identificar polimorfismos potencialmente causais em genes candidatos associados a características reprodutivas em novilhas, por meio de dois ensaios. No primeiro, foram sequenciadas regiões dos genes PPP3CA e FABP4 em 380 amostras de DNA provenientes de novilhas Nelore, por meio de equipamento MiSeq® (Illumina, Inc). Nestas sequências foram detectadas duas mutações na região do gene PPP3CA e 13 no gene FABP4. Dentre elas, 14 eram SNP e uma era deleção, sendo esta última homozigota em todas as amostras sequenciadas, o que nos leva a acreditar que possa ser uma mutação fixada na raça Nelore. Um haplótipo constituído por quatro SNP no gene FABP4 não teve efeito significativo ao nível de p<0,05 sobre a característica OPP. Todos os SNP que passaram pelo controle de qualidade também foram analisados, porém nenhum teve efeito significativo sobre a característica OPP (p>0,05). No segundo ensaio, foram analisadas sequências de amostras de RNA de novilhas Brangus com o objetivo de identificar polimorfismos nas regiões de 62 genes candidatos associados a características reprodutivas. Detectou-se 1157 SNP nas regiões de 46 daqueles genes. Esses SNP foram comparados com SNP detectados a partir de sequências de amostras de RNA de outras quatro raças (Angus, Brahman, Nelore e Holandês). Cento e setenta e dois SNP foram coincidentes em todas as raças. A partir de sequências de RNA de Brangus também foram detectados 160 novos transcritos na região de 42 dos genes candidatos e cinco genes não anotados que sobrepõem a região de genes candidatos. A detecção de novos transcritos e genes é fundamental para enriquecer a anotação do genoma bovino. As mutações detectadas podem ser utilizadas para a customização de painéis de marcadores, e aplicações de seleção genômica.
Fertility traits such as age at puberty are economically important for meat production system. Occurrence of early pregnancy (OPP) is considered a good indicator of age at puberty and can be used as selection criteria. The search for causal mutations in candidate genes can helpful to improve the accuracy of genomic prediction if used to design low-density chips. The objective of this study was to identify polymorphism in candidate genes associated with puberty in heifers. DNA sequences were obtained from 380 Nellore heifers from exons sequencing of PPP3CA and FABP4 genes through MiSeq® equipment (Illumina, Inc.). From these sequences were found two SNP in the region of PPP3CA gene and 13 variations in the gene FABP4. Among these 15 variations 12 were SNP and one was a deletion, and this deletion was detected in all samples sequenced, which leads us to conclude that this may be a variation between Nellore and Hereford. One haplotype consisting of four SNP located in the FABP4 and nine SNP, that were analyzed separately, had not a significant effect at the p <0.05 on OPP characteristic. Also were analyzed RNA sequences from Brangus heifers in 62 candidate genes associated with puberty with the aim to discovery SNP in these regions. Were detected 1157 SNP in the region of 46 gene. These SNP were compared with SNP detected from RNA sequences from four breeds, Angus, Brahma, Nellore and Holstein. One hundred and seventy-two SNP were matched in all breeds. From Brangus RNA sequences were also detected 160 new transcripts in the region of 42 candidate genes and five genes not annotated that overlap the region of candidate genes. Detection of new transcripts and genes is essential to enrich the bovine genome annotation. The mutations detected can be used for the customization of low density chips and future genomics selection strategies.
Fertility traits such as age at puberty are economically important for meat production system. Occurrence of early pregnancy (OPP) is considered a good indicator of age at puberty and can be used as selection criteria. The search for causal mutations in candidate genes can helpful to improve the accuracy of genomic prediction if used to design low-density chips. The objective of this study was to identify polymorphism in candidate genes associated with puberty in heifers. DNA sequences were obtained from 380 Nellore heifers from exons sequencing of PPP3CA and FABP4 genes through MiSeq® equipment (Illumina, Inc.). From these sequences were found two SNP in the region of PPP3CA gene and 13 variations in the gene FABP4. Among these 15 variations 12 were SNP and one was a deletion, and this deletion was detected in all samples sequenced, which leads us to conclude that this may be a variation between Nellore and Hereford. One haplotype consisting of four SNP located in the FABP4 and nine SNP, that were analyzed separately, had not a significant effect at the p <0.05 on OPP characteristic. Also were analyzed RNA sequences from Brangus heifers in 62 candidate genes associated with puberty with the aim to discovery SNP in these regions. Were detected 1157 SNP in the region of 46 gene. These SNP were compared with SNP detected from RNA sequences from four breeds, Angus, Brahma, Nellore and Holstein. One hundred and seventy-two SNP were matched in all breeds. From Brangus RNA sequences were also detected 160 new transcripts in the region of 42 candidate genes and five genes not annotated that overlap the region of candidate genes. Detection of new transcripts and genes is essential to enrich the bovine genome annotation. The mutations detected can be used for the customization of low density chips and future genomics selection strategies.
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Palavras-chave
Características Reprodutivas, DNA, RNA, SNP, Transcritos, Fertility Traits, Transcripts