Wisdom teeth: refining our understanding of mammalian evolution through dating dental enamel

智齿：通过测定牙釉质加深我们对哺乳动物进化的理解

• 批准号: NE/S010211/1
• 负责人: Kirsty Penkman
• 金额: $ 82.48万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS010211%2F1
• 关键词: Wisdom; teeth; refining; our; understanding

Directly dating mammal fossils older than the limit of radiocarbon dating (~50,000 years) is very challenging, and this has led to a research focus on the most recent past in forming our understanding of mammalian response to changing environments. However this narrow time window is extremely limiting if we aim to understand the effects of climate change on land-based organisms, or unpick our own evolutionary history. We are hard-pressed to pinpoint the major evolutionary drivers for African mammals, and to compare patterns across a large, diverse continent. This problem notably includes our own ancestors. The fundamental problem preventing the required comparisons is chronology, and specifically a method that can date fossils directly. Our project team has been developing and employing methods for dating using the breakdown of the original proteins trapped within fossils. Excitingly, we have just made a methodological breakthrough which enables amino acid (a protein breakdown product) dating to be undertaken on the small amounts of amino acids remaining in tooth enamel (a resistant crystalline material composed of calcium phosphate with small amounts of protein). Dating enamel has the enormous advantage of providing a direct date on mammal teeth (critical fossils of interest) and the new method now enables routine amino acid analysis, successfully dating UK material up to 3 million years in age. This technique is ripe for development to a range of mammalian species and additional geographic regions, potentially revolutionising our understanding of mammalian evolution (including humans) during the last few million years, and their response to environmental change, at the local and the global scale.This proposal will address the three areas of technology development needed for this dating method to be used routinely, but the time frame it opens up (the last ~4 million years) will enable a significant shift in the range of research questions we can address. The three strands of technological advance proposed are: 1) a microfluidics ("lab on a chip") approach, which will enable both a significant decrease in the physical sample size needed, as well as preparation / analyses to be undertaken outside specialist labs; 2) combining analysis and imaging of both the organic and inorganic fractions to understand their structure, function and any impact on the protein breakdown; and 3) using advanced chemical models to understand the breakdown reactions.We will then apply these methods to two regions of Africa of particular evolutionary interest: east Africa (including the Rift Valley) and southern Africa (including the 'Cradle of Humankind'). Initially calibrating the dating approach on reliably dated material, we will then expand it to material that is currently of unknown age. The developed chronology will also enable models of human-environment interaction to be tested, providing a breakthrough in our understanding of our evolutionary past. This project will therefore take the latest advances in dating and apply them to a region where the palaeoenvironmental record can help shape the understanding of the sensitivity of Africa's biota (plants and animals) to changes in temperature and rainfall patterns. Understanding large mammals' responses to environmental and climate change is critical for developing appropriate conservation measures, and we will also gain insights into the timings and drivers of the evolution of our human lineage.

直接测定哺乳动物化石的年龄超过放射性碳测年的极限（约50，000年）是非常具有挑战性的，这导致了研究重点放在最近的过去，以形成我们对哺乳动物对环境变化的反应的理解。然而，如果我们的目标是了解气候变化对陆地生物的影响，或者解开我们自己的进化历史，那么这个狭窄的时间窗口是非常有限的。我们很难确定非洲哺乳动物的主要进化驱动力，也很难比较这片巨大而多样的大陆的模式。这个问题包括我们的祖先。阻止所需比较的根本问题是年代学，特别是可以直接确定化石年代的方法。我们的项目团队一直在开发和采用利用化石中捕获的原始蛋白质分解的方法。令人兴奋的是，我们刚刚取得了方法上的突破，能够对牙釉质中剩余的少量氨基酸（一种由磷酸钙和少量蛋白质组成的抗性晶体材料）进行氨基酸（一种蛋白质分解产物）测年。测定牙釉质的年龄具有巨大的优势，可以提供哺乳动物牙齿（感兴趣的关键化石）的直接日期，新方法现在可以进行常规氨基酸分析，成功地测定了英国材料长达300万年的年龄。这项技术已经成熟，可以发展到一系列哺乳动物物种和其他地理区域，可能会彻底改变我们对哺乳动物进化的理解（包括人类）在过去几百万年中的变化，以及他们对环境变化的反应，在当地和全球范围内。这项建议将解决三个领域的技术发展所需的这种定年方法，以定期使用，但它所开启的时间框架（过去~ 400万年）将使我们可以解决的研究问题范围发生重大转变。提出的三条技术进步是：1）微流体（“芯片上实验室”）方法，这将使得所需的物理样品大小以及在专业实验室之外进行的制备/分析显著减少; 2）将有机和无机部分的分析和成像相结合，以了解它们的结构、功能和对蛋白质分解的任何影响; 3）使用先进的化学模型来理解分解反应。然后我们将这些方法应用于非洲两个特别具有进化意义的地区：东非（包括裂谷）和南部非洲（包括“人类的摇篮”）。最初，我们在可靠的年代测定材料上校准测年方法，然后将其扩展到目前年龄未知的材料。开发的年表还将使人类与环境相互作用的模型得到测试，为我们对进化历史的理解提供突破。因此，该项目将利用测年方面的最新进展，并将其应用于一个区域，在该区域，古环境记录可以帮助形成对非洲生物群（植物和动物）对温度和降雨模式变化的敏感性的理解。了解大型哺乳动物对环境和气候变化的反应对于制定适当的保护措施至关重要，我们还将深入了解人类谱系进化的时间和驱动因素。

项目成果

Intra-crystalline protein degradation dating of enamel

牙釉质晶内蛋白降解年代测定

• 发表时间: 2020
• 作者: Dickinson MR

Amino acid dating of mammalian tooth enamel and its potential for building geochronologies in Africa

哺乳动物牙釉质的氨基酸测年及其在非洲建立地质年代学的潜力

• 发表时间: 2020
• 作者: Dickinson MR

Wisdom Teeth: Sample preparation of mammoth tooth enamel for dating using amino acid racemization

智齿：猛犸象牙釉质样品制备，用于使用氨基酸外消旋定年

• 发表时间: 2021
• 作者: Patinglag L

Intra-crystalline protein degradation dating of enamel from Stanton Harcourt

斯坦顿哈考特牙釉质的晶内蛋白质降解年代测定

• 发表时间: 2021
• 作者: Dickinson MR

Amino acid dating of mammalian tooth enamel and its potential for building geochronologies

哺乳动物牙釉质的氨基酸测年及其构建地质年代学的潜力

• 发表时间: 2021
• 作者: Dickinson MR