Genetic polymorphisms of the IGF-II gene intron 8 coding region and its association with growth and carcass traits in yak.
Genetic polymorphisms of the IGF-II gene intron 8 coding region and its association with growth and carcass traits in yak.
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DOI：
10.4238/2013.december.11.11
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
Y. Zeng;X. Ding;S. Cheng;S. J. Yu
中科院分区：
文献类型：
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作者：
Y. Zeng;X. Ding;S. Cheng;S. J. Yu
胰岛素样生长因子II（IGF-II）在哺乳动物生长中起关键作用，并参与刺激胎儿细胞分裂、分化和代谢调节。IGF-II被认为是生长和胴体性状遗传标记的候选基因。因此，在本研究中，IGF-II基因区域的单核苷酸多态性（SNPs）与生长和胴体性状在5个牦牛品种的关联进行了研究。通过对纯合子中IGF-II基因的内含子8进行测序，发现了两个SNP，G（330）C和A（358）G。通过聚合酶链反应鉴定出两个等位基因A和B以及三种基因型AA、AB和BB。IGF-II等位基因B在大通牦牛、甘南牦牛、天祝白色牦牛、青海高原牦牛和新疆牦牛中的基因型频率分别为0.8623、0.8936、0.8535、0.8676和0.8300。IGF-II的等位基因和基因型与生长和胴体性状密切相关。最小二乘法分析表明，AA和AB基因型对12、13-24和25-36月龄的活重、日增重和胴体重的影响均极显著（P <0.01），而BB基因型对12、13-24和25-36月龄的胴体重的影响均极显著（P <0.05）。具有基因型AB的动物具有较高的平均肋眼面积和较低的平均产量等级。结果表明，IGF-II基因的作用主要是通过增加体重的生物学机制，而不依赖于骨骼的生长。
Insulin-like growth factor II (IGF-II) plays a key role in mammalian growth and is involved in stimulating fetal cell division, differentiation, and metabolic regulation. IGF-II is considered a candidate gene for genetic markers of growth and carcass traits. Therefore, in this study, the associations of single nucleotide polymorphisms (SNPs) in the IGF-II gene region with growth and carcass characteristics in five yak breeds were investigated. Two SNPs, G(330)C and A(358)G, were identified by sequencing intron 8 of the IGF-II gene in homozygotes. Two alleles, A and B, and three genotypes, AA, AB, and BB, were identified by polymerase chain reaction. Genotypic frequencies of IGF-II allele B were 0.8623, 0.8936, 0.8535, 0.8676, and 0.8300 for Datong yak, Gannan yak, Tianzhu white yak, Qinghai Plateau yak, and Xinjiang yak, respectively. Allele and the genotype of IGF-II were strongly associated with growth and carcass traits. Least square analysis revealed a significant effect (P < 0.01) of genotypes AA and AB compared with genotype BB on live-weight (at 12, 13-24, and 25-36 months of age), average daily weight gain (P < 0.01) and carcass weight (P < 0.05). Animals with genotype AB had a higher mean rib eye area, and a lower mean yield grade. The results indicated that the IGF-II gene acts by a primarily additive biological mechanism by adding weight independently of skeletal growth.