【作者】 涂荣剑；

【导师】 邓昌彦；

【作者基本信息】 华中农业大学 ， 动物遗传育种与繁殖， 2003， 硕士

【摘要】 猪肉品质改良一直是家畜育种工作者工作的主要目标之一，随着现代人民生活水平的不断提高，生产质优量多的猪肉显得尤为重要。 本研究以与猪脂肪代谢有关的候选基因—解耦联蛋白基因3（UCP3）为研究对象，利用139头大白×梅山资源家系F₂代及321头F₁代资源家系（81头大梅、55头梅山、30头大白、43头长白、46头梅大、35头长大、31头大长），研究了UCP3基因3’编码区及3’调控区的多态性和遗传效应，结果如下： 1、UCP3基因3’编码区的克隆测序及SNP检测---PCR-SSCP分析 根据猪UCP3基因的cDNA序列设计引物，对四个品种猪：大白、梅山、杜洛克、清平猪肌肉样提取总RNA进行反转录和特异性扩增，得到含UCP3基因3’编码区的扩增产物，经克隆及测序，对不同品种猪该区段序列进行比较分析，发现3个突变位点（SNPs），选取其中一个（ORF内第842碱基C→T突变）能引起错义突变（甲硫氨酸→苏氨酸）的位点为标记位点进行标记基因型--性状的关联分析。 （1）利用PCR-SSCP在139头大白×梅山资源家系F₂代及321头F₁代资源家系（81头大梅、55头梅山、30头大白、43头长白、46头梅大、35头长大、31头大长）中进行了UCP3基因3’编码区的该标记位点基因型的分子扫描，发现：UCP3基因表现出3种基因型（AA、AB、BB），结果显示：A等位基因频率在大白×梅山资源家系F₂代、大白×梅山资源家系F₁代个体及大白、长白、大长、长大群体中分布频率较高，其频率范围为0.71-0.87，而B等位基因则分布较低，其频率范围为0.13-0.29；在梅山、梅大两个群体中，B等位基因分布频率相对较高，分别是0.56、0.55。 （2）139头大白×梅山资源家系F₂代个体UCP3基因多态性与遗传效应分析—UCP3基因不同基因型对胴体性状的影响： UCP3基因多态性与猪胸腰椎间膘厚极显著相关（P＜0.01），UCP3^AA基因型个体胸腰椎间膘厚比UCP3^AB基因型个体低14.2％；同时UCP3基因多态性与猪眼肌高度、眼肌面积显著相关（P＜0.05），UCP3^AB基因型个体眼肌高度、眼肌面积分别比UCP3^BB基因型个体高7.8％和11.2％。 在胴体性状方面，UCP3基因主要以加性作用方式发挥作用，眼肌高度、估测瘦肉率加性效应值分别为-0.348（P＜0.05），-9.218（P＜0.01）。 （3）139头大白×梅山资源家系F₂代个体UCP3基因多态性与遗传效应分析—UCP3基因不同基因型对肉质性状的影响： UCP3基因多态性与失水率、系水率及背最长肌色值显著相关，UCP3^AA基因型猪解祸联蛋白基因3（UCP3）的序列及多态性分析个体失水率比UCP3“B基因型个体低4.00，0（P<0.05），其系水率则比ueP3“B基因型个体高8.3%（P<0.05），uCP3n日基因型个体背最长肌色值比ucP3从基因型个体高18.2%（P<0.05）:此外，UCP3基因多态性与水分（LD）极显著相关，UCP3AB基因型个体水分比UCP3AA基因型个体低0.65%（P<0.01）。此外，在脂肪含量（LD）方面，UcP3AB基因型猪比uCP3AA基因型个休高8.1%，达建议显著水平（P二0.067）。 在肉质性状方面，UCP3基因主要以加性作用方式发挥作用，显性效应不显著。失水率、系水率及背最长肌色值的加性效应值分别为2.759（P<0.05），一3.759 （P<0 .05），2.012（P<0.05）。 （4）81头大白、梅山资源家系FI代个体UCP3基因多态性与遗传效应分析一UCP3基因不同基因型对朋体性状的影响: 研究表明:UCP3基因多态性与肩部背膘厚相关显著:UCP3从基因型个体肩部背膘厚比UCP3”“基因型个体高11 .3%（P<0.05）;除此外，未发现在该家系中UcP3不同基因型与其它性状的相关。2 UCP3基因3’调控区Aval多态性位点的遗传效应分析 利用猪DNA对UCP3基因3’调控区的一碱基变异区段进行PCR扩增，对其扩增产物的Aval酶切位点进行PCR一PFLP分析，并在1 39头大白又梅山参考家系FZ代个体中进行多态性扫描和遗传效应分析，结果表明:该多态位点的不同基因型与猪胭体及肉质性状相关均不显著。并且该位点基因除在水分性状（LD）中的加性效应值显著外:一0.388（P<0.05），其它性状的加性、显性效应也都不显著。 本实验结果表明:UCP3基因3’编码区突变位点的多态性与猪胭体性状:胸腰椎间膘厚、眼肌高度、眼肌面积及肉质性状:失水率、系水率、背最长肌色值和水分（LD）相关显著，同时与脂肪含量（LD）的相关达建议显著水平;并且，该基因片段以加性效应为主，有利于在育种过程中的遗传固定。因此，建议是否将此标记基因在猪标记辅助选择一肉质品质及胭休品质改良中加以应用。更多还原

【Abstract】 Improvement of porcine meat quality is always one of the main goals for livestock genetics and breeding.At present.It is more important for technicians to produce pork with the lean and good quality,while people tend to be interested in meat quality when the standard of living condition has been improved.In this paper,we selected the Uncoupling Protein Gene-3(UCP3) as the candidate gene for carcass and meat quality,and meanwhile analyzed its gene effects and the pattern of effects.1. doing of UCP3 gene 3’-cDNA translated region and detection method of its single polymorphism(SNP)-PCR-SSCPUsing the porcine cDNA sequence.primers of UCP3 gene were designed and were applied to amplify the gene from four different porcine total RNA of longissimus dorsi muscle.Four breeds’ fragments of 574bp length were got and we compared the differences of their sequences.The compared results showed that there were three single nucleotide mutations in UCP3 gene 3’-cDNA translated region, of which the mutation of 842bp in ORF can result in the change of ammo acid sequence.PCR-SSCP scanning of 139 F2 and 321 Fl individuals of pig resource families showed that:(1) UCP3 gene showed three genotypes(AA,AB and BB).Their disstribution indicated that allele A seemed predominant in the following populations: Large Whitex Meishan F2 and Fl, Large White, Landrace, Large White Landrace, Landrace x Large White, and the ranges of allele frequencies was 0.71-0.87;in contrast.allele B was 0.13-0.29.However,the frequencies of allele B were 0.56 and 0.55 respectively.(2) Association analyzing of UCP3 polymorphism with carcass traits in 139 F2 Large WhitexMeishan individualsSignificant association between the UCP3 genotypes and thorax-waist fat thickness,height and area of longissimus dorsi muscle(LD) was found.Pigs with the AA genotype had approximately 14.2% less average thorax-waist fat thickness than those with the AB genotype(P<0.01)and the height and area of longissimus dorsi muscle(LD) of BB genotype individuals were 7.8% and 11.2% less than AB genotype ones(P<0.05).UCP3 gene played a role mainly in the pattern of additive effect on carcass traits.The additive effect values of longissimus dorsi muscle height and estimated lean meat percentage were -0.348(P<0.05) and -9.281 respectively(P<0.01).(3) Association analyzing of UCP3 polymorphism with meat quality traits in 139 F2 Large WhitexMeishan individualsIt showed that UCP3 genotypes had significant association with water lost rate, water holding capacity, meat color(LD)(P<0.05), and water(LD) (P<0.01).The AA genotype individuals had 4.0%, 18.2% respectively less than BB genotype ones in waterlost rate, meat color, but had 8.3% more water holding capacity than pigs with BB genotype. To the water(LD),the AA genotype pigs were 0.65 more than AB ones.We also found that UCP3 gene’ additive effect on meat quality predominated in the population,and the additive effect values of water lost rate,water holding capacity,meat color(LD) were 2.750(P<0.05), -3.795(P<0.05), -2.012 (P<0.05) respectively.(4)Scanning results of UCP3 polymorphism on carcass traits in 81 Fl Large WhitexMeishan resource familyExcept for the significant association with shoulder fat thickness(P<0.05),we found no more significance in the association with other carcass traits. It showed that the BB genotype pigs were 11.3% less should fat thickness than AA genotype ones.2. UCP3 gene 3’-UntransIated Region’ polymorphismThe 696bp fragement of UCP3 gene 3’-Untranslated Region was gained after amplifying. Using Ava I , PCR-RFLP scanning in 139 F2 resource family indicated that there was no significant association of 3’-Untranslated Region’ polymorphism with carcass traits and meat quality traits as well. However, the region of UCP3 gene seemed to play a mainly additive effect on water(LD):-0.388(P<0.05).更多还原