The Evo-Devo of Vertebrate Teeth & Jaws

进食是生存的基础。动物头部的大小和形状很大程度上受动物吃的食物类型的影响。推动脊椎动物进化研究的一个核心问题是，动物的头部如何在不损害重要功能和部位的情况下多样化，包括牙齿和支撑牙齿的下巴。为了进食并存活下来养育后代，动物的牙齿和下巴必须在正确的地点、正确的时间正确发育。尽管科学家和公众对牙齿和脸部有着浓厚的兴趣，但协调牙齿和下巴生长的发育遗传过程仍然是个谜。解释这些过程对于理解物种如何发展、进化和适应吃各种食物至关重要。在包括人类在内的一些物种中，牙齿和下巴对于交流也很重要，比如发出声音和面部表情。此外，人类牙齿和下巴的进化很可能与我们的文化进化交织在一起，特别是工具的使用和烹饪。我的NSERC资助的研究项目的长期愿景是揭示牙齿和颌骨组织相互影响彼此的发育和进化的程度(Evo-Devo)，并通过这种方式帮助解释史前和现存物种生动多样的面孔和饮食。我们对这个持续不断的问题的切入点是研究缺失p63基因表达的无牙小鼠。我和我的受训者发现了一个由p63控制的基因网络，它是下颌骨形成的附带因素，但对牙齿发育是必需的，我们认为这种基因网络允许牙齿进化，而不会迫使颌骨发生变化。我们有强有力的证据表明，这个基因网络控制着老鼠、猴子和鱼类的牙齿发育。我们的下一步是研究这些基因在哪里、如何以及为什么在这三个动物群体的牙齿中起作用。我们将从老鼠那里收集数据，以测试网络中哪些基因直接相互对话，并确定这个网络的链接。为了揭示这些基因在老鼠身上的作用，我们将通过实验阻止每个基因在发育中的牙齿中的活动。在鱼身上，我们将测试这个基因网络是否只作用于口腔内的牙齿，还是也作用于喉咙内的牙齿。同时，我们将定义这些基因在猴子物种牙齿中的作用，包括一些与人类关系更密切的物种。我们对这些基因如何协同工作、它们起什么作用以及在牙齿发育过程中在哪里工作的新知识，不仅将推动我们的研究目标和视野，而且将对生物学家、生态学家、人类学家以及牙医具有更广泛的价值。我的团队结合了发育遗传学、3D成像、统计形状和对硬头组织和软头组织的解剖学分析，来定义和建模限制或促进包括人类祖先在内的有齿下颌的形态进化的因素。我的包容性实验室文化倡导公平和多样性。学员积累了大量急需的专业技能，使他们在自然科学和工程研究以及教育、工业和政策领域的工作中具有竞争力。

Eating is essential to survival. Animal head size and shape is heavily influenced by the types of foods animals eat. A core question driving studies of vertebrate evolution is how animal heads diversified without compromising vital functions and parts, including teeth and the jaws that hold them. To eat and survive to raise offspring, an animal's teeth and jaws must develop properly in the right place, at the right time. Despite keen scientific and public interest in teeth and faces, the developmental-genetic processes that coordinate tooth and jaw growth remain mysterious. Explaining these processes is vital to understand how species develop, evolve, and adapt to eat a variety of foods. In some species, including humans, teeth and jaws are also important for communication, such as making sounds and facial expressions. Also, human tooth and jaw evolution is likely entwined with our cultural evolution, notably tool use and cooking. The long-term vision of my NSERC-funded research program is to reveal the extent to which dental and jaw tissues influence each other's development and evolution (evo-devo) and, in this way, help explain the vivid, varied faces and diets of prehistoric and living species. Our wedge into this persistent question was to study toothless mice missing the expression of a gene, p63. My trainees and I discovered a network of genes controlled by p63 incidental to mandible formation but required for tooth development that we think allows teeth to evolve without forcing the jaw skeleton to change. We have strong evidence that this gene network controls tooth development in mice, monkeys, and fish. Our next step is to study where, how, and why these genes act in the teeth of these three animal groups. We will collect data from mice to test which genes in the network speak to each other directly, and define the links of this network. To reveal what these genes do in mice, we will experimentally block each gene's activity in the developing tooth. In fish, we will test if this gene network acts in teeth within the mouth only or also teeth within the throat. In parallel, we will define where these genes act in the teeth of monkey species, including some more closely related to humans. Our new knowledge about how these genes work together, what they do, and where during tooth development will not only advance our research aims and vision but will also be valuable more broadly to biologists, ecologists, anthropologists, as well as dentists. My team combines developmental genetics, 3D imaging, statistical shape and anatomical analyses of hard and soft head tissues to define and model the factors that constrain, or facilitate, morphological evolution of the toothed jaw including in human ancestors. My inclusive lab culture champions equity and diversity. Trainees accrue a host of in-demand professional skillsets, making them competitive for jobs in natural science and engineering research, and in education, industry, and policy.