Genome-wide Mining Of Olfactory Receptor Genes Affecting Pig Growth And Feeding

Growth-related traits have high economic value in pigs,most of the growth related traits are quantitative traits,which are controlled by minor-polygene.Studies have shown that genetic variation of olfactory receptor(OR)genes among domestic animals was not only associated with feeding behavior,food choice,and energy balance regulation,but also with some production traits.Therefore,this study aims to mining OR genes affecting growth traits of pig using copy number variation(CNV)association analysis and quantitative trait locus(QTL)mappingin.In addition,the genetic parameters of feeding behavior and production traits were estimated and the genome-wide association study(GWAS)of feeding behavior were also carried out.The main results of this study were as follows:Part1.CNVRs detection and growth trait CNV-GWASUsing the CNVcaller software,3099 CNVRs were detected among 591 Large White pigs×Min pig F2 intercross pig population.And among these CNVRs,a totoal of 6 CNVRs are multi-copy,and 818 are both missing and multi-copy.Based on the resequcing data,CNV-GWAS was conducted with six growth traits containing body length(BL),body height(BH),shoulder width(SW),waist width(WW),circumference of cannon bone(CCB)and 180 day old body weight(180dW),and 5 CNVRs were found highly associate with growth traits in pigs of F2 generation(P<1.61E-5).In addition,the CNV of the OR12D3 gene in the CNVR2091 interval could significantly affect the BH trait(P<0.01).In addition,we also founded that the CNV in OR12D3 gene increased,and the BH trait increased accordingly by qPCR verification.Part2.Genetic linkage map construction and growth trait QTL mappingBased on resequencing data,we built the high-density genetic map of Large White pigs×Min pig F2 intercross population.The total map distance in this genetic map was 2210.41 cM,and the average distance between adjacent markers was 0.38 cM.Furthermore,fourteen QTLs were identified to be related to growth traits of F2 generation pigs via genome-wide QTL mapping.The candidate gene for olfactory receptors affecting BL traits was OR12D3 in the significant QTL interval.In addition,the candidate olfactory receptor genes affecting BH traits were OR12D3 and OR13H1,and the candidate OR genes affecting SW traits was OR6C65.The results were consistent with the results of CNV association analysis and suggested that the olfactory receptor genes may be associated with pig growth.Part3.Genetic parameter estimation and GWAS analysis of feeding behavior and production traitsEight feeding behaviors and production traits including the average daily intake(ADI),average times of daily intake(ATDI),average time spent feeding per visit(ATPV),average intake per visit(AIPV),feeding intake rate(FR),average daily gain(ADG),residual feed intake(RFI),feed conversion ratio(FCR)were are used to estimate genetic parameters in the 1080 Duroc populations.GWAS analysis was performed using resequencing data of the 100 Duroc populations.By the results of genetic parameter estimating,we found that there are high genetic correlation between ADI and ADG,ADI and RFI,AIPV and ADG(r_g>0.6),which indicated that feeding behavior could affect the growth.In GWAS analysis of the Duroc population,RUFY3,NDUFAB1,PAX4 genes were selected as candidate genes for ATPV traits through candidate gene screening.OR52W1,ATL3,NXF1,SPAG6,LGALS12 were selected as candidate genes for FCR traits.OR10J5 was selected as candidate genes for ADI traits.OR52W1、OR8D4、OR10S1were selected as candidate genes for ATDI traits,and OR51E1 was selected as candidate genes for FR traits.In this study,we acquired 8 OR genes significantly associated with growth and feeding behavior traits using genome-wide CNV association analysis,QTL mapping,and the relationship between OR12D3gene and pig body height traits was verified by qPCR..This study provides a certain foundation for further understanding the function of OR gene and molecular breeding.