Dissertation Research: Reconstructing a mitogenome-based intraspecific tree to test for phylogenetic inertia in a morphological study of island dwarfing in Southeast Asian mammals

这个项目探讨了在岛屿上孤立的哺乳动物会发生什么。根据一个概括称为？岛屿规则？由于食物资源严重有限，岛屿上的大型物种有一种进化出较小体型（岛屿侏儒化）的趋势。然而，很少有人研究个体解剖学成分的变化，如大脑大小和头骨形状，这些变化伴随着身体尺寸的减小。这项研究的总体目标是探索东南亚大型哺乳动物的岛屿和大陆代表：鹿，猪和灵长类动物之间大脑大小和头骨形态的潜在差异。这项研究将使用DNA测序来解决岛屿人口之间的关系，并在统计分析中考虑到这些关系。由于这项研究是在芝加哥的菲尔德博物馆进行的，研究人员积极参与了针对博物馆游客的广泛的外展计划，这些计划允许成年人和学生了解岛屿上的进化。通过对岛屿上哺乳动物多样性的研究，将有助于公众了解生命的进化史。本项目将探讨种内亲缘关系如何影响岛屿哺乳动物的头骨形态和大脑大小。为了实现这一目标，研究人员将重点放在长尾猕猴，Macaca fascicularis，因为它是东南亚最广泛的灵长类动物物种。他们将基于整个线粒体基因组为博物馆标本生成一个很好的解决群体水平的同源性。DNA将首先从伊利诺伊大学香槟分校一个无菌的古代DNA实验室的博物馆标本的干燥组织样本中提取。然后，科学家们将为每个样本建立遗传文库，并使用特定的富集技术仅针对线粒体的基因组。然后将这些富集的样品用于高通量测序。由此产生的线粒体序列将被修剪和组装，用于重建一个强大的物种内同源性。推断的树将用于控制脑大小和头骨形态的统计分析中的相关性，并深入了解（a）M. fascicularis，特别是较小的岛屿，和（B）总体的地理格局和多样化的速度。

This project explores what happens to mammals isolated on islands. According to a generalization known as the ?Island Rule?, there is a trend on islands for large-bodied species to evolve smaller body size (island dwarfing) because food resources are severely limited. However, little work has been done on changes in individual anatomical components, such as brain size and skull shape, that accompany decreases in body size. The overall goal of this research is to explore potential differences in brain size and skull morphology between island and mainland representatives of large-bodied mammals in Southeast Asia: deer, pigs and primates. The research will use DNA sequencing to resolve relationships among island populations and take these relationships into account during statistical analyses. Because this research is based at The Field Museum in Chicago, the researchers are actively involved with a wide range of outreach programs directed toward museum visitors, which allow both adults and students to learn about evolution on islands. Together, the outreach and investigation of mammal diversification on islands will contribute to public understanding of the evolutionary history of life.This project will explore how intraspecific relatedness influences skull morphology and brain size in island mammals. To achieve this, researchers will focus on the long-tailed macaque, Macaca fascicularis, because it is the most widespread primate species in Southeast Asia. They will generate a well-resolved population-level phylogeny for museum specimens based on entire mitochondrial genomes. DNA will first be extracted from dried tissue samples from museum specimens in a sterile, ancient DNA lab at University of Illinois Urbana-Champaign. Then, the scientists will build genetic libraries for each sample and target only the genomes of the mitochondria using specific enrichment techniques. These enriched samples will then be used for high-throughput sequencing. The resulting mitochondrial sequences will be trimmed and assembled, for reconstruction of a robust within-species phylogeny. The inferred tree will be used to control for relatedness in statistical analyses of brain size and skull morphology, and to gain insights into (a) the relative timing of colonization of Southeast Asian islands by M. fascicularis, especially of smaller islands, and (b) overall phylogeographic patterns and rates of diversification.