Uncovering the primate clitoris

揭开灵长类动物的阴蒂

• 批准号: NE/X012603/1
• 负责人: Charlotte Brassey
• 金额: $ 9.85万
• 依托单位: Manchester Metropolitan University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX012603%2F1
• 关键词: Uncovering; primate; clitoris

All female mammals have a clitoris. The clitoris plays a vital role in arousal, sexual pleasure, and orgasm. Yet we know very little about this structure and how it has evolved. The 'pea-sized' external part of the human clitoris is just the tip of the iceberg: 90% of the structure lies hidden under the skin. Such details of the human clitoris were only revealed in the last two decades, following the use of medical imaging technology, such as MRI and X-ray CT. Even less is known about the clitoris of our closest kin, the primates. Whilst distinctive skin swellings around the genitals have been documented in females of many species, we know almost nothing of the internal anatomy of the clitoris. How many nerve endings are present? Where is the clitoris most 'sensitive'? How might tissues change shape during arousal? Without this information from other primate species, it is impossible to understand the evolutionary forces that have shaped the form and function of the human clitoris, nor human sexual behaviour.The lack of understanding does not extend to male reproductive organs. The equivalent structure in males, the penis, is comparatively well-studied. This may reflect a societal bias, where female genitalia were historically thought to be less variable than male counterparts and therefore overlooked. This one-sidedness may also relate to technical challenges associated with studying the clitoris. Compared to male genitals, female tissues are often small, delicate, and hidden from view. Recent advances in biological imaging, however, ensure these hurdles can now be overcome.In this project, we will develop new methods for studying the primate clitoris. They will allow us, for the first time, to understand the structure of the clitoris, from gross anatomy to microscopic features, across the family tree of primates. Cadavers will come from the National Museum of Scotland, which is the main repository for deceased UK zoo animals. Sampled females will include lemurs, loris, marmosets, macaques, gibbons, and apes. Meticulous dissection of the perineal region will be required, to both describe the clitoral anatomy and to extract the tissues without damage for further analysis. An anatomical guide exists only for human cadavers, and dissections will therefore be extremely novel and exploratory.Once dissected out, the clitoral tissue will be sliced very thinly, stained with dyes and viewed under a microscope, a process referred to as histology. These 'thin sections' will be used to document the number of nerve endings and their distribution across several areas of the clitoris. To better understand the 3D shape of the primate clitoris, the pelvic regions from additional cadavers will be x-ray microCT scanned. This will allow for a non-destructive 'virtual dissection' of the whole clitoris (including the hidden tissue), allowing us to better understand its shape and function by ensuring clitoris remain undisturbed within the animal's pelvic region. The resulting models will be the first ever glimpse into 3D structure and shape of the primate clitoris, beyond our currently limited understanding of human females.Having established the feasibly of extracting such valuable information from highly prized museum specimens, the proposed project will open several avenues for further research. In mammals, reproduction ultimately requires the direct interaction of male and female genitals. The idea that female and male reproductive structures should evolve together is generally accepted and yet, remarkably, has never been tested in our closest relatives, the primates. Using the techniques developed in this project, future research will explore the size and shape of primate genitals, as well as interactions between male and female anatomy during sex. These advances will revolutionise the study of sexual selection in this group and transform our understanding of the natural history of human genitalia and human sexuality.

所有雌性哺乳动物都有阴蒂。阴蒂在性唤醒、性愉悦和性高潮中起着至关重要的作用。然而，我们对这种结构以及它是如何演变的知之甚少。豌豆大小的人类阴蒂外部只是冰山一角：90%的结构隐藏在皮肤之下。人类阴蒂的这些细节直到最近20年才被发现，之后使用了医学成像技术，如核磁共振和X射线CT。对我们近亲灵长类动物的阴蒂更是知之甚少。虽然许多物种的雌性生殖器周围有独特的皮肤肿胀，但我们对阴蒂的内部解剖几乎一无所知。有多少神经末梢？阴蒂在哪里最“敏感”？在性唤醒过程中，组织可能会如何改变形状？如果没有其他灵长类物种的这些信息，就不可能理解塑造人类阴蒂形式和功能的进化力量，也不可能理解人类的性行为。缺乏理解并不延伸到男性生殖器官。对男性的同等结构--阴茎--的研究相对较多。这可能反映了一种社会偏见，在历史上，女性生殖器被认为比男性生殖器更少变化，因此被忽视。这种片面性也可能与研究阴蒂相关的技术挑战有关。与男性生殖器相比，女性的组织通常很小，很脆弱，而且隐藏在人们的视线之外。然而，生物成像的最新进展确保了这些障碍现在可以克服。在这个项目中，我们将开发研究灵长类阴蒂的新方法。它们将第一次让我们了解阴蒂的结构，从大体解剖到微观特征，跨越灵长类的系谱。身体将来自苏格兰国家博物馆，那里是英国动物园已故动物的主要储存库。被采样的雌性将包括狐猴、懒猴、绒猴、猕猴、长臂猿和猿类。需要对会阴区进行细致的解剖，既要描述阴蒂的解剖结构，又要在不损伤的情况下提取组织进行进一步分析。解剖学指南只适用于人类身体，因此解剖将非常新颖和探索性。一旦解剖出来，阴蒂组织将被切得非常薄，用染料染色，并在显微镜下观察，这一过程被称为组织学。这些“薄片”将被用来记录神经末梢的数量及其在阴蒂几个区域的分布。为了更好地了解灵长类阴蒂的3D形状，将对更多身体的骨盆区域进行X射线微CT扫描。这将允许对整个阴蒂(包括隐藏的组织)进行非破坏性的虚拟解剖，通过确保阴蒂在动物的骨盆区域内保持不受干扰，使我们能够更好地了解阴蒂的形状和功能。所产生的模型将是有史以来第一次瞥见灵长类阴蒂的3D结构和形状，超出了我们目前对人类女性的有限了解。这个拟议的项目建立了从珍贵的博物馆标本中提取如此有价值的信息的可行性，将为进一步研究开辟几条途径。在哺乳动物中，生殖最终需要雄性和雌性生殖器的直接相互作用。雌性和雄性生殖结构应该一起进化的想法被普遍接受，但值得注意的是，从未在我们的近亲灵长类身上进行过测试。利用该项目开发的技术，未来的研究将探索灵长类生殖器的大小和形状，以及性交过程中男性和女性解剖之间的相互作用。这些进展将彻底改变这一群体的性选择研究，并改变我们对人类生殖器和人类性行为自然历史的理解。