Monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B) are enzymes that degrade several monoamines of the central nervous system and have long been implicated in the modulation of social behavior. Macaque monkeys are a suitable model for investigating the role of functional monoamine oxidase polymorphisms in behavior modulation given the high amount of social diversity among the nearly two dozen species. The present study reports allele frequencies for two polymorphisms, MAOA-LPR and MBin2, in samples of rhesus (Macaca mulatta) and Japanese (M. fuscata) macaques. Our results suggest that the two species may differ in high- and low-activity MAOA-LPR allele frequencies. Specifically, 89% of the Japanese macaque alleles in our sample were the low-activity variant, whereas only 41% of the rhesus macaque alleles were of this sort. In our samples, the two species possessed similar allelic variation at the MBin2 locus, with each possessing some species-specific alleles. We also tested for associations between MAOA-LPR genotype and plasma serotonin (5-HT) and dopamine (DA) concentrations in a subset of rhesus macaques, which revealed no association with genotype. Our findings point toward potential differences in the monoaminergic system of two closely related macaque species. Discussion of our results are centered on implications for future investigations that aim to better understand the functionality of monoamine oxidase polymorphisms in the context of primate social behavior.

中文翻译：

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恒河猴和日本猕猴（Macaca mulatta 和 M. fuscata）的单胺氧化酶多态性

单胺氧化酶 A (MAO-A) 和单胺氧化酶 B (MAO-B) 是降解中枢神经系统的几种单胺的酶，长期以来一直与社会行为的调节有关。鉴于近两打物种之间的大量社会多样性，猕猴是研究功能性单胺氧化酶多态性在行为调节中的作用的合适模型。本研究报告了恒河猴 (Macaca mulatta) 和日本 (M. fuscata) 猕猴样本中两种多态性 MAOA-LPR 和 MBin2 的等位基因频率。我们的结果表明，这两个物种的高活性和低活性 MAOA-LPR 等位基因频率可能不同。具体来说，我们样本中 89% 的日本猕猴等位基因是低活性变体，而只有 41% 的恒河猴等位基因属于这种类型。在我们的样本中，这两个物种在 MBin2 基因座上具有相似的等位基因变异，每个物种都具有一些物种特异性等位基因。我们还测试了恒河猴亚组中 MAOA-LPR 基因型与血浆血清素 (5-HT) 和多巴胺 (DA) 浓度之间的关联，这表明与基因型没有关联。我们的发现指出了两种密切相关的猕猴物种的单胺能系统的潜在差异。我们的结果的讨论集中在对未来调查的影响上，这些调查旨在更好地了解灵长类动物社会行为背景下单胺氧化酶多态性的功能。我们还测试了恒河猴亚组中 MAOA-LPR 基因型与血浆血清素 (5-HT) 和多巴胺 (DA) 浓度之间的关联，这表明与基因型没有关联。我们的发现指出了两种密切相关的猕猴物种的单胺能系统的潜在差异。我们的结果的讨论集中在对未来调查的影响上，这些调查旨在更好地了解灵长类动物社会行为背景下单胺氧化酶多态性的功能。我们还测试了恒河猴亚组中 MAOA-LPR 基因型与血浆血清素 (5-HT) 和多巴胺 (DA) 浓度之间的关联，这表明与基因型没有关联。我们的发现指出了两种密切相关的猕猴物种的单胺能系统的潜在差异。我们的结果的讨论集中在对未来调查的影响上，这些调查旨在更好地了解灵长类动物社会行为背景下单胺氧化酶多态性的功能。