The vomeronasal organ (VNO) plays a key role in sensing pheromonal cues, which elicit social and reproductive behaviors. Although the VNO is highly conserved across mammals, it has been lost in some species that have evolved alternate sensing systems during diversification. In this study, we investigate a newly identified VNO-specific gene, ancV1R, in the extant 261 species of mammals to examine the correlation between genotype (ancV1R) and phenotype (VNO). As a result, we found signatures for the relaxation of purifying selection (inactivating mutations and the elevation of dN/dS) on ancV1Rs in VNO-lacking mammals such as catarrhine primates, cetaceans, the manatees, and several bat lineages, showing the distinct correlation between genotype and phenotype. Interestingly, we further revealed signatures for the relaxation of purifying selection on ancV1R in true seals, otters, the fossa, the owl monkey, and alcelaphine antelopes in which the existence of a functional VNO is still under debate. Our additional analyses on TRPC2, another predictive marker gene for the functional VNO, showed a relaxation of purifying selection, supporting the possibility of VNO-loss in these species. The results of our present study invite more in-depth neuro-anatomical investigation in mammals for which VNO function remains equivocal.

中文翻译：

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灭活ancV1R作为哺乳动物中犁鼻系统损失的一种预测特征。

犁鼻器（VNO）在感知信息素提示中起关键作用，信息素提示引发社交和生殖行为。尽管VNO在整个哺乳动物中都高度保守，但在某些物种中已经消失，这些物种在多样化过程中发展了替代的传感系统。在这项研究中，我们调查了现有的261种哺乳动物中新发现的VNO特异性基因ancV1R，以检查基因型（ancV1R）与表型（VNO）之间的相关性。结果，我们在缺乏VNO的哺乳动物（如卡他碱灵长类动物，鲸类，海牛和一些蝙蝠谱系）的ancV1Rs上发现了放松纯化选择（失活突变和dN / dS升高）的特征，显示出明显的相关性在基因型和表型之间。有趣的是 我们进一步揭示了在真正的海豹，水獭，窝，猫头鹰猴和阿奇拉非羚羊中，对在ancV1R上纯化选择的放松，其中仍存在功能性VNO的争议。我们对TRPC2（功能性VNO的另一个预测性标记基因）的进一步分析显示，纯化选择的放宽，支持了这些物种中VNO损失的可能性。我们目前的研究结果邀请对VNO功能仍然模棱两可的哺乳动物进行更深入的神经解剖学研究。支持这些物种中VNO损失的可能性。我们目前的研究结果邀请对VNO功能仍然模棱两可的哺乳动物进行更深入的神经解剖学研究。支持这些物种中VNO损失的可能性。我们当前研究的结果邀请对VNO功能仍然模棱两可的哺乳动物进行更深入的神经解剖学研究。