大白×梅山杂交组合肉质性状的数量性状位点定位分析

为寻找影响猪肉质数量性状基因位点的染色体区域 ,以 3头英系大白公猪和 7头梅山母猪建立F2 资源家系。随机选留 14 7头F2 代个体 (1998年 81头 ,2 0 0 0年 66头 ) ,经检测均获得肉质性状表型数据。对资源家系内的所有个体位于染色体 1、2、3、4、6和 7上的 48个微卫星位点进行扩增。利用线性模型最小二乘法分别对各年度及两年综合后的肉质性状进行数量性状位点 (QTL)区间定位 ,利用置换法确定显著性阈值。研究结果表明 :在 2 0 0 0年群体中 ,猪 4号染色体 (SSC4)上定位了肌内脂肪QTL ,达到染色体极显著水平 (P <0 0 1)和基因组显著水平 (P <0 0 5) ,解释表型变异为 5 2 4% ,梅山猪具有增加肌内脂肪QTL ;两年度群体综合后 ,在上述 4号染色体同一区间 ,肌内脂肪QTL接近染色体显著水平 ;股二头肌pH值和半棘肌pH值QTL分别定位在SSC1和 3上 ;在 1998年和 2 0 0 0年群体中分别发现 1个和 3个达染色体显著水平 (P <0 0 5)的系水力QTL ;在 1998年群体中 ,肌肉含水量QTL位于SSC6;两年综合群体中 ,SSC2、6和 7上定位了肌肉含水量QTL ,达到染色体显著水平 ,含水量QTL均有印迹效应 ,梅山和大白猪各有增效基因

Mapping Quantitative Trait Loci for Meat Quality Trait in a Large White×Meishan Cross

To search for the chromosome regions for quantitative trait loci (QTL) affecting meat quality in pigs,a three-generation resource family was developed in China using three Large White grand sires and seven Meishan grand dams.A total of 147 F_2 progenies derived from two populations in 1998 (n=81) and 2000 (n=66) were phenotyped for meat quality.All animals were typed for 48 microsatellite markers covering six chromosomes:1,2,3,4,6 and 7.Linear model and least square analyses were used for interval mapping meat quality in jointed population and single population,permutation for empirical threshold.The strongest linkage at chromosome-wide level (P<0.01) and genome-wide level (P<0.05) on chromosome 4 affecting intramuscular fat (IMF) QTL from the population in 2000 was detected with explained phenotypic variance of 5.24%,and Meishan's QTL increased the intramuscular fat content.There was a suggestive QTL for IMF near the threshold of chromosome-wide in the same region in jointly population.The QTL for pH value in m.Semispinalis Capitis and m.Biceps Femoris were located on chromosomes 1 and 3,respectively.One and three QTL affecting WHC reached the thresholds of chromosome-wide level in the populations of 1998 and 2000,respectively.In the population of 1998,QTL for moisture content at chromosome-wide level was on SSC6 and in jointed populations were on SSC2,6 and 7.There were imprinting effects in moisture content QTL,and Meishan and Large White pigs all had favorable effects influencing moisture on different chromosomes.