Abstract：
Context Several polymorphisms in the melatonin receptor 1A gene (MTNR1A ) have been related to reproductive performance in ovine. Aims To investigate the effect of the Rsa I and Mnl I polymorphisms on ram seminal quality. Methods Eighteen Rasa Aragonesa rams were genotyped for the Rsa I (C/C, C/T, T/T) and Mnl I (G/G, G/A, A/A) allelic variants of the MTNR1A gene. Individual ejaculates were analysed once a month throughout the whole year. Sperm motility, morphology, membrane integrity, levels of reactive oxygen species (ROS), phosphatidylserine (PS) inversion, DNA fragmentation and capacitation status were assessed. The effect of the season and polymorphisms on seminal quality was evaluated by mixed ANOVA. Key results Both polymorphisms had an effect on membrane integrity and viable spermatozoa with low levels of ROS and without PS translocation, and Rsa I also on motile and DNA-intact spermatozoa. An interaction between both polymorphisms was found, pointing to a negative effect on seminal quality of carrying the T or A allele in homozygosity. Differences were higher in the reproductive than in the non-reproductive season. Conclusions Mutations substituting C by T and G by A at Rsa I and Mnl I polymorphic sites, respectively, in the MTNR1A gene in rams could decrease the seminal quality. Implications Genotyping of rams based on melatonin receptor 1A could be a powerful tool in sire selection.
摘要：
背景褪黑素受体1A基因（MTNR1A）的几种多态性与绵羊的生殖性能有关。目的探讨RsaI和MnlI多态性对公羊精液质量的影响。方法对18只RasaAragonesa公羊进行RsaI基因分型(C/C，C/T,T/T)和MnlI(G/G，G/A,A/A)MTNR1A基因的等位基因变体。全年每月分析一次个体射精。精子运动,形态学,膜完整性,活性氧（ROS）的水平，磷脂酰丝氨酸(PS)倒置,评估DNA片段化和获能状态。通过混合方差分析评估季节和多态性对精液质量的影响。关键结果两种多态性都对膜完整性和存活精子有影响，ROS水平低，没有PS易位，和RsaI也在活动和DNA完整的精子上。发现了两种多态性之间的相互作用，指出纯合性携带T或A等位基因对精液质量有负面影响。生殖季节的差异高于非生殖季节。结论在RsaI和MnlI多态性位点，用T代替C和用A代替G的突变，分别,公羊的MTNR1A基因可降低精液质量。含义基于褪黑激素受体1A的公羊基因分型可能是选择母羊的有力工具。
