Wang Xinyu, Yang Qing, Wang Ke, Yan Hailong, Pan Chuanying, Chen Hong, Liu Jinwang, Zhu Haijing, Qu Lei, Lan Xianyong
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi, 712100, PR China.
College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi, 712100, PR China; Shaanxi Provincial Engineering and Technology Research Center of Cashmere Goats, Yulin University, Yulin, Shaanxi, 719000, PR China; Life Science Research Center, Yulin University, Yulin, Shaanxi, 719000, PR China.
Theriogenology. 2019 Feb;125:115-121. doi: 10.1016/j.theriogenology.2018.10.013. Epub 2018 Oct 19.
Growth differentiation factor 9 (GDF9) gene is an effective intra-ovarian regulator; it plays a crucial role in early folliculogenesis in female mammals. The non synonymous mutations: g.3905A > C (also known as p.Gln320Pro/Q320P) and g.4135G > A (also know as p.Val397Ile/V397I), are two well-known and controversial single nucleotide polymorphisms (SNPs) within GDF9 gene in goats with different prolificacy, and so far, there were no studies on linkage between Q320P and V397I. Therefore, the aim of this work was to study whether Q320P and V397I mutations have a significant effect on litter size, in Shaanbei white cashmere goats (SBWC, n = 1511), and to explore the specific relationship between these two SNPs. The results showed that both of Q320P and V397I mutations exhibited three genotypes; the minor allele frequencies (MAF) of the SNPs were 0.286 and 0.477, respectively; and these two SNPs were in strong linkage disequilibrium (D' = 0.976, r = 0.348) in the studied goats. Moreover, association analyses revealed that Q320P was significantly associated with the first-born litter size in goats irrespective of the sample size (n = 1511; P = 0.008), while V397I significantly affected litter size until the sample size crossed 1300 (P = 0.015). Meanwhile, the diplotypes PP-II and QP-VI were observed to have a superior effect on litter size (P = 3.78 × 10) to that of the haplotypes (P = 1.12 × 10). Thus, the findings led us to assume that Q320P mutation was the major SNP affecting goat litter size. These findings can provide useful DNA markers for selecting superior individuals in marker-assisted selection (MAS) for breeding in relation to fecundity in goats.
生长分化因子9（GDF9）基因是一种有效的卵巢内调节因子；它在雌性哺乳动物早期卵泡发生过程中起着关键作用。非同义突变：g.3905A > C（也称为p.Gln320Pro/Q320P）和g.4135G > A（也称为p.Val397Ile/V397I），是山羊GDF9基因内两个著名且存在争议的单核苷酸多态性（SNP），其繁殖力不同，到目前为止，尚未有关于Q320P和V397I之间连锁关系的研究。因此，本研究的目的是研究Q320P和V397I突变对陕北白绒山羊（SBWC，n = 1511）产仔数是否有显著影响，并探讨这两个SNP之间的具体关系。结果表明，Q320P和V397I突变均表现出三种基因型；这些SNP的次要等位基因频率（MAF）分别为0.286和0.477；在研究的山羊中，这两个SNP处于强连锁不平衡状态（D' = 0.976，r = 0.348）。此外，关联分析显示，无论样本量大小（n = 1511；P = 0.008），Q320P与山羊头胎产仔数显著相关，而V397I直到样本量超过1300时才对产仔数有显著影响（P = 0.015）。同时，观察到双倍型PP-II和QP-VI对产仔数的影响优于单倍型（P = 3.78 × 10）（P = 1.12 × 10）。因此，这些发现使我们推测Q320P突变是影响山羊产仔数的主要SNP。这些发现可为山羊繁殖力的标记辅助选择（MAS）中选择优良个体提供有用的DNA标记。
