牛DGAT2基因第6内含子MspI-RFLPs和TaqI-RFLPs及其与牛经济性状相关性研究

利用PCR-RFLPs方法分析牛DGAT2基因第5、6和7内含子内部的MspI和TaqI等11种酶切多态性,并在第6内含子检测到MspI-RFLPs和TaqI-RFLPs 2个多态位点。分析表明,该MspI-RFLPs普遍存在于鲁西牛、晋南牛、秦川牛、利木赞×鲁西牛、西门塔尔×延边牛、夏洛来×延边牛、安格斯×延边牛和三河牛、中国荷斯坦牛等9个试验群体中,TaqI-RFLPs只在鲁西牛、晋南牛和秦川牛3个地方品种和利木赞与鲁西牛的杂交群体中检测到,而且等位基因B(T碱基)在除鲁西牛外的群体中分布频率很低。统计分析表明,MspI-RFLPs与肉牛的体脂没有相关,但显著影响屠宰率,AA型个体的屠宰率显著高于AB和BB型(P<0.05)。DGAT2基因第6内含子MspI酶切多态性与三河牛群体平均乳脂率和平均干物质含量有极显著或显著的相关性(P<0.01和P<0.05),AA型个体的平均乳脂率和平均干物质含量均高于BB型个体的均值,但在荷斯坦牛群体中却没有得到相同的结果。研究分析了鲁西牛中TaqI-RFLPs的AA型与AB型个体之间屠宰性能的差异,结果表明这2种基因型与鲁西牛的屠宰性能没有显著的相关(P>0.05),有待在更大的鲁西牛群体中检验TaqI-RFLPs是否影响屠宰性状。

MspI-RFLPs and TaqI-RFLPs in DGAT2 Intron 6 and Their Effects on Bovine Economic Traits

PCR-RFLPs assay was used to investigate polymorphisms within the cloned introns 5 to 7.A MspI-RFLPs and a TaqI-RFLPs were detected in intron 6.The MspI-RFLPs is common in all the detected breeds,but the TaqI-RFLPs only was founded in Chinese breeds,and allele B(bearing T base) is rare in Chinese breeds.Associations between the founded MspI-RFLPs in intron 6 and carcass traits in the seven beef cattle breeds and two Chinese dairy cattle were tested,no relation between MspI-RFLPs and body fat in beef cattle were founded in present study,but the individuals bearing AA genotype had higher(P<0.05)dressing percentage.Individuals with genotype AA had higher milk fat percentage(P<0.01)and dry material percentage(P<0.05)in Sanhe.For the TaqI-RFLPs in intron 6,the present study only tested the carcass trait's difference between genotype AA and AB in Luxi cattle,but no associations were founded.