猪肉色相关QTL整合定位与基因关联分析

Meta-analysis of meat color QTL in swine

【目的】通过构建整合图谱和Meta分析,利用数学模型整合与优化猪肉色相关QTL,分析已知候选基因与"真实"QTL(MQTL)的关联性,为肉色性状的分子标记辅助选择奠定基础。【方法】收集猪肉色相关QTL,包括明度系数(L值,MCOLORL)、红度值(a值,MCOLORa)和黄色度(b值,MCOLORb)等指标,利用BioMercator2.1软件,将原始QTL映射到美国肉畜研究中心(USDA-MARC 2.0)公布的猪遗传连锁图谱中,构建整合图谱,分析得到QTL簇;对各QTL簇进行Meta分析,定位MQTL;进一步将已知候选基因映射到整合图谱,比较候选基因与各MQTL在染色体上的位置关系,分析其关联性。【结果】将176个猪肉色相关QTL进行比对、映射后,构建成新的整合图谱。通过Meta分析,将原本分散的QTL定量合并为37个MQTL,其中MQTL2、MQTL3、MQTL8～MQTL11、MQTL13～MQTL16、MQTL18～MQTL20、MQTL24、MQTL25、MQTL29、MQTL31、MQTL32、MQTL35～MQTL37共21个MQTL的缩短比例均超过50%,MQTL9、MQTL19、MQTL11、MQTL28、MQTL35、MQTL8、MQTL2、MQTL3等8个MQTL的置信区间在5cM内。【结论】获得了37个猪肉色性状,图距1.16～22.68cM,较原QTL图距均有不同程度地缩短,缩短比例为25.19%～90.33%,提高了QTL定位的准确度和有效性。

【Objective】 This study was performed for the Quantitative Trait Loci（QTL） related to meat color to estimate the number and refine the positions of QTL with meta-analysis.【Method】 An integrated map of meat color QTL which included MCOLORL,MCOLORa and MCOLORb was established with the swine linkage map of USDA-MARC 2.0 as a reference map.With the software BioMercator2.1,initial QTL was collected and projected to the reference map.Meta-QTL（MQTL）was obtained by meta-analysis which reduced the QTL confidence intervals compared with individual QTL estimates.Positions of candidate genes and meta-QTL obtained in this study were compared with reckon the precision of meta-QTL.【Result】 176 meat color QTL collected from 20 published papers were converged to 37 meta-QTL,and their corresponding markers were obtained.The confidence intervals of meta-QTL,with 21 of which were shrunk more than 50% and 8 of which were reduced to less than 5 cM compared with the QTL before the meta-analysis.For instance,the confidence interval of MQTL9,MQTL19,MQTL11,MQTL28,MQTL35,MQTL8,MQTL2,MQTL3 was only 1.16,2.43,2.45,4.18,4.29,4.40,4.73,4.88 cM,respectively.【Conclusion】 The confidence interval of meta-QTL ranged from 1.16 cM to 22.68 cM,with the reduction rate changed from 25.19% to 90.33%.These results offered more precise QTL position estimates,and a basis for gene mining and molecular breeding in swine.