| Feed cost is typically 60% of total cost of pig production. Feed efficiency was the one of the decisive factor for cost of pig production, especially under the condition of intensive breeding.Therefore, conclude important candidate genes, study and improve the index of feed utilization efficiency through genetic breeding method were the important problems need to be solved. However,the major gene and regulation mechanism of feed utilization efficiency was unclear. In this study, a Genome-Wide Association Study(GWAS) was used to analysis the candidate gene of feed utilization efficiency related traits in Duroc population. Analyse the function and define causative mutations of candidate gene in this article and existing research. High-throughput RNA-seq was used to carry out the mRNA expression in the hypothalamus pituitary tissues of high and low RFI Duroc. And figure out the regulatory pathways and networks. Major contents in this research are as follows.1. The arm of this part was to identify the function of candidate gene MAP3K5 and GPX2 for Residual feed intake trait in this Duroc population. There are no full length of MAP3K5, so we cloned5451 bp full-length cDNA of MAP3K5, obtained the gene structure and gene expression profile. And found that the copy number of MAP3K5 gene have the significant different in high and low RFI Duroc.The two SNPs of MAP3K5 have the significant association with RFI, one SNP of MAP3K5 have the significant association with FCR, one SNP of MAP3K5 have the significant association with ADG. A total of 7 SNPs were identified in exon and 5’flank region of GPX2. These SNPs didn’t have the significant correlation with RFI traits. However, the seven SNPs of GPX2 have the significant associated with 100 kg BF and other growth characters. The GPX2 expression was significantly different between back fat in different genotype.2. The TASSEL software was used to acquire the RFI traits that calculated by six formula modes in613 Duroc population. This research discovered that the six different calculate method have a little influence on GWAS results, and the most SNPs were consisted in six RFIs. Only One SNP was genome-wide significantly associated with six RFI traits. The 9 SNPs were significant associated with RFI1-6. Six candidate genes(e.g. MTERF3 etc) were observed. We detected the 5 significant association SNPs in FCR traits and seven candidate genes for FCR trait(e.g. PLA1 A etc.)3. The TASSEL software was used to acquire the feed utilization efficiency eight related traits(e.g.ADFI, LEA etc.) in 613 Duroc populations. We only detected the 6 significant SNPs associated with LEA trait which concentrate located in chromosome 12 and 9, and these SNPs showed linkage disequilibrium. One SNP distributed on chromosome 3. All significant SNPs for LEA were located nearest with six genes(e.g. HLF etc.). There were no significant SNP for other seven traits.4. We used RNA-seq to generate the porcine transcriptome from hypothalamus pituitary tissues of low and high RFI Duroc. And we found more than 12000 new transcripts. Low RFI group compared with high RFI group, 112 differently expressed genes have been detected, and 37 genes were the up-regulated gene, 75 genes were the down-regulated gene. These gene were enriched in the Biologicalprocesses and signaling pathways which included neuroactive ligand-receptor interaction, inositol phosphate metabolism, calcium signaling pathway, adrenergic signaling in cardiomyocytes. The candidate gene of GWAS was partly expressed in hypothalamus pituitary tissues of low and high RFI Duroc. Apart of the gene have the close relationship with phospholipid metabolism and neuroregulation.In this paper, we found that the MAP3K5 may be the candidate gene for feed efficiency related trait in this Duroc populations.We found the several candidate genes(MTERF3、PLA1A and HLF etc) for RFI, FCR and ADG traits by GWAS. Phospholipid metabolism and neuroregulation involved in regulating the RFI trait in hypothalamus pituitary tissues... |
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