鸭胸肌肌内脂肪含量全基因组关联分析

Genome-wide Association Analysis of Intramuscular Fat in Duck

肌内脂肪含量与肉品质密切相关。本研究构建了北京鸭×绿头野鸭F_2代群体,利用索氏提取法测定了F_2代130只个体(66♂,64体)的胸肌肌内脂肪含量,并分析该性状与胸肌厚度、腹脂重、肌纤维面积和肌纤维直径的相关性,之后采用全基因组关联分析(GWAS)鉴定胸肌肌内脂肪相关基因。结果显示:MTDFREML软件估计北京鸭×绿头野鸭F_2代群体肌内脂肪含量的遗传力为0.39,与胸肌厚、腹脂重、肌纤维面积和肌纤维直径的表型相关性分别为0.44、0.20、0.44和0.42;GWAS分析发现达到染色体显著水平P<2.39×10^(-7)(1/4 182 586)的SNP共9个,分别位于3个区间;位于1号染色体的关联区间为4.2~4.38Mb,对相关性最强的点进行基因分型发现TT基因型对应的个体肌内脂肪沉积能力更强;位于8号染色体的区间为5.0~5.6 Mb,该区域内包含9个基因;在16号染色体的关联区间为3.4~3.6 Mb,对相关性最强的点进行基因分型,发现CC基因型个体脂肪沉积相对较多。研究鉴定的3个连锁区间可作为分子标记用于肉鸭高肌内脂肪品系的选育。

Intramuscular fat content determines the meat quality.We constructed Pekin duck and mallard segregation population to illuminate the genetic basis of intramuscular fat(IMF).The IMF contents of 130 F2 population individuals(66 males and 64 females)were measured using soxhlet extraction method,and calculated the relevance of breast meat thickness(BMT),abdominal fat weight(AFW),muscle fiber area(MFA),muscle fiber diameter(MFD)to IMF,and the heritability of IMF was estimated using MTDFREML.We performed genome-wide association analysis(GWAS)to identify the associated genes with IMF.The results showed the heritability of IMF was 0.39,which belonged to medium genetic traits,and genetic correlation between BMT,AFW,MFA,MFD and IMF were 0.44,0.20,0.44 and 0.42,respectively.The results showed that a total of 9 suggestive SNPs among 3 regions passed the GWAS threshold(P<2.39×10^(-7),1/4182586).A region span 0.18 Mb(4.2-4.38 Mb)on duck chromosome 1 was identified to be associated with IMF.Nine genes located in this region span 0.18 Mb(4.2-4.38 Mb)on duck chromosome 8 associated with IMF.A region of span 0.2 Mb(3.4-3.6 Mb)on duck chromosome 16 was found to be associated with IMF.Three regions significantly associated with IMF were identified,which could be used as the molecular markers for the breeding of high intramuscular fat stains.