Evolution of mammalian venom: a molecular, ecological and morphofunctional approach

项目描述：在许多不同的谱系中，毒液系统的多个独立招募突出了毒液特征在动物界进化中的生物学重要性。研究确定，毒液系统的进化主要是为了提供防御性功能(如鱼、蜜蜂)或捕食性功能(如蛇、蜘蛛)。很少有现存的哺乳动物是有毒的，所有已知的有毒哺乳动物都是基本目的代表，如鸭嘴兽和一些脂鳞虫(Whittington等人。2010)。这表明毒液有一个古老的进化起源，并有可能对哺乳动物进化的大范围模式有新的见解(Fox&Scott，2005；Turvey 2010)。有毒的加勒比海白鲨是现存的唯一拥有改良的牙齿毒液输送系统和专门的口腔毒腺的哺乳动物。然而，哺乳动物毒液系统的进化起源、蛋白质组成和功能仍然知之甚少。因此，这个项目旨在通过解决以下问题来研究剑齿龙为什么有毒液系统，它是做什么的，以及它是如何进化的：1.剑齿龙的毒液可能起到捕食、防御或种内竞争的作用？2.剑齿龙的毒素成分和生化活性是什么？3.剑齿龙的毒液系统与其他已知毒液能力的哺乳动物(如鸭嘴兽、地鼠)的毒液系统是否同源，以及其他真脊椎动物(如鼹鼠、刺猬)是否表现出毒液系统的证据？这将通过多学科的方法来实现。该学生将进行肌肉骨骼和生物力学分析，比较脂肪鞘头骨的解剖和功能，以确定毒液的生态作用(在没有咬合力的情况下制伏猎物？防御性的？种内竞争？)(Rayfield 2007；Gill et al.2014年)。这将与加勒比地区的实地研究结合起来，作为ZSL既定方案的一部分，以确定Solenodon的饮食和种内社会互动。实地工作还包括收集剑齿龙毒液、唾液和血液样本，以补充现有样本，这些样本将用于研究剑齿龙蛇毒的分子生物学--表征蛇毒蛋白质组，并使用功能分析来表征雄性和雌性蛇毒的生物活性。

Project description:The biological importance of the venomous trait in the evolution of the animal kingdom is highlighted by the multiple independent recruitments of venom systems in many distinct lineages. Research has determined that venom systems evolved primarily to provide defensive (e.g. fish, bees) or predatory (e.g. snakes, spiders) functions. Very few extant mammals are venomous, and all known venomous mammals are representatives of basal orders such as the platypus and some lipotyphlans (Whittington et al. 2010). This suggests an ancient evolutionary origin for venom and the potential for new insights into broad-scale patterns of mammalian evolution (Fox & Scott, 2005; Turvey 2010). The venomous Caribbean solenodons are the only extant mammals to possess modified dental venom delivery systems and specialised oral venom glands. However, the evolutionary origin, protein composition and function of mammalian venom systems remain very poorly understood. This project therefore aims to investigate why solenodons have a venom system, what does it do, and how did it evolve, by addressing the following questions:1. Does solenodon venom likely function for predation, defence, or intraspecific competition?2. What is the toxin composition and biochemical activity of solenodon venom?3. Are the venom systems of solenodons homologous to those of other mammals with known venom capacity (e.g. platypus, shrews), and do other eulipotyphlans (e.g. moles, hedgehogs) exhibit evidence of a venom system?This will be achieved via a multidisciplinary approach. The student will conduct musculoskeletal and biomechanical analyses of comparative lipotyphlan skull anatomy and function to determine the ecological role of venom (to subdue prey in absence of bite strength? for defence? intraspecific competition?) (Rayfield 2007; Gill et al. 2014). This will be combined with field studies in the Caribbean as part of the ZSL established programme, to determine solenodon diet and intraspecific social interactions. Fieldwork will also involve collecting solenodon venom, saliva and blood samples, to supplement existing samples that will be used to address the molecular biology of solenodon venom - characterising the venom proteome and using functional assays to characterise male and female venom bioactivity.