Genetic variants of the GDF9 gene were considered to be the potent gene markers for improving fecundity traits in Egyptian sheep and goats. Also, these favorable gene variants could be applied in the breeding program by gene-assisted selection (GAS), aiming towards the potential amelioration of reproduction and production in such small ruminants. The present investigation was designed to evaluate the genetic variants of the GDF9 gene on fecundity traits including the mean number of lambing “MNL” and mean number of twin production “MNTP” of Egyptian sheep and goats. This experiment involved 113 mothers, 83 of sheep and 30 of goats, at first, second, third, and fourth parity, and also 26 young females, 12 of sheep and 14 of goats at age of sexual maturation. T-ARMS-PCR analysis was performed on five mutation points (G1, G4, G6, G7, and G8). In sheep, the heterozygous mothers of G4 had significant elevation (P ≤ 0.05) of MNL and MNTP than wild-type homozygous ewes. However, the heterozygous mothers of G1 and G6 gave a reduction of MNL and MNTP as compared to mothers with wild-type genotypes. The ewes of G7 had heterozygous genotype (AG), and the ewes of G8 had wild type (CC). In goat, G4 and G7 were polymorphic, and G1, G6, and G8 were monomorphic type. Based on these findings, it must be selected the young sheep females of heterozygous in G4, and the young goat females of heterozygous in G4 and G7 for participating in a successful breeding program, because they will have potential high fecundity traits. The present results confirmed that the genetic variants of the GDF9 gene were considered to be the major gene markers for enhancement of the prolificacy in Egyptian sheep and goats and could be applied in a successful breeding program by gene-assisted selection (GAS) in small ruminants.

中文翻译：

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GDF9基因突变点及其与埃及小反刍动物繁殖力的关系研究

GDF9 基因的遗传变异被认为是改善埃及绵羊和山羊繁殖力性状的有效基因标记。此外，这些有利的基因变体可以通过基因辅助选择 (GAS) 应用于育种计划，旨在改善此类小型反刍动物的繁殖和生产。本研究旨在评估 GDF9 基因在繁殖性状上的遗传变异，包括埃及绵羊和山羊的平均产羔数“MNL”和平均双胞胎生产数“MNTP”。该实验涉及 113 名母亲、83 只绵羊和 30 只山羊，分别在第一胎、第二胎、第三胎和第四胎，以及 26 只年轻雌性、12 只绵羊和 14 只性成熟的山羊。对五个突变点（G1、G4、G6、G7 和 G8）进行 T-ARMS-PCR 分析。在羊中，与野生型纯合母羊相比，G4 的杂合子母羊的 MNL 和 MNTP 显着升高（P ≤ 0.05）。然而，与具有野生型基因型的母亲相比，G1 和 G6 的杂合母亲的 MNL 和 MNTP 减少。G7母羊为杂合基因型（AG），G8母羊为野生型（CC）。山羊G4、G7为多态型，G1、G6、G8为单态型。基于这些发现，必须选择 G4 杂合子雌性幼羊和 G4 和 G7 杂合子母山羊幼崽参与成功的育种计划，因为它们将具有潜在的高繁殖力性状。