Qtl mapping for drip loss in a white duroc × erhualian f2 resource population | 在白色杜洛克×二花脸资源家系中定位影响猪肉滴水损失的QTL

中国人. 目的通过全基因组扫描，鉴别影响猪肉滴水损失数量性状位点（QTL）。方法采用EZ-滴水损失测定法和袋测定法，测定了白色杜洛克×二花脸资源群体884头F2代个体的背最长肌和半膜肌在采样后24和48 h的滴水损失。利用SAS软件分析了6个滴水损失性状间的相关性，以及滴水损失与其它肉质性状的相关性。检测了3个世代个体在19条染色体上194个微卫星的基因型。据此，应用QTL Express在线进行了影响滴水损失QTL的定位分析。结果滴水损失在两种肌肉间或两种测定方法间有较高的相关性（r = 0.50―0.58，P＜0.01），而在两个连续测定时间点间相关性更高（r = 0.72，P＜0.01）。滴水损失与24 h的pH、肉的亮度（Minolta L），肉色评分、大理石纹、水分含量及肌内脂肪含量呈中等或较低的显著相关（r = 0.09―0.35，P＜0.05）。QTL分析共检测到9个影响滴水损失相关性状的QTL，6个背最长肌滴水损失QTL，分别位于SSC1、SSC10和SSC12，其中SSC10上的QTL达到5%基因组显著水平；影响半膜肌滴水损失的3个QTL分别位于SSC2、SSC6和SSC17上。结论在SSC6、SSC10、SSC12及SSC17上首次检测到滴水损失QTL。多个滴水损失QTL与早先定位的pH QTL或肌内脂肪含量QTL的置信区间重叠。检测到的QTL无一个既影响背最长肌滴水损失，又影响半膜肌滴水损失。大部分QTL有利等位基因（减少滴水损失）源自二花脸猪。

英语. Objective A genome-wide scanning was performed to detect quantitative trait loci (QTL) for drip loss. MethodUsing EZ-DripLoss and bag methods, drip loss of longissimus muscle (LM) and semimembranous muscle (SM) were measured at 24 and 48 h after sampling in 884 F2 animals from a White Duroc×Erhualian resource population. The correlations among 6 drip loss traits and between drip loss and other meat quality traits were analyzed by SAS version 9. All pigs in this experimental population were genotyped for 194 informative markers covering the entire porcine genome. QTL were identified by regression interval mapping using the online software of QTL Express. Result Correlation between the drip loss of two muscles or between drip loss obtained by two methods were high (r= 0.50-0.58, P＜0.01) , and the correlation between consecutive measurements was higher (r=0.59-0.72, P＜0.01). Drip loss was correlated with pH24h, Minolta L, subjective color score, marbling, moisture content and intramuscular fat content at moderate or low levels (r=0.09-0.35, P＜0.05). A total of 9 QTLs were identified, including 6 QTLs for drip loss of LM on SSC2, SSC10 and SSC12; the one on SSC10 reached the 5% genome-wide significant level. Three QTLs for drip loss of SM were detected on SSC2, SSC6 and SSC17. Conclusion Four novel QTL on SSC6, SSC10, SSC12 and SSC17 were identified. Several QTL for drip loss overlapped with previously mapped QTL for pH or intramuscular fat content. None of QTL affected drip loss of both LM and SM. Erhualian founders carried favorable alleles (decreasing drip loss) at most of the detected QTL.