Collaborative Research: Bivalves in time and space: testing the accuracy of methods to reconstruct ancestral morphology, dates, geography, and diversification patterns

该项目旨在将双壳类软体动物发展为跨越很长一段时间的进化研究的卓越模型。利用DNA序列数据和形态学的组合，将构建两个双壳类家族的进化系统树(系统发育图)，即双壳类/巨蚌和双壳类。这些系统发育将包括200个现存物种和100-200个灭绝物种，并将与计算机模拟和特殊的双壳类化石记录相结合，以测试进化估计和重建中常用方法的准确性。具体地说，该项目将测试使用活着物种的数据来估计历史上祖先的年龄、身体特征和地理分布的方法。现代比较生物学的几乎每一个方面都建立在这样一个假设之上，即系统发育可以用来重建各种祖先属性的进化。但是，基于活物种的重建具有广泛的不确定性，因为这些方法还没有根据化石记录中所代表的准确历史进行测试。双壳类是这项工作的理想选择，因为它们今天很丰富，而且有丰富的化石记录。通过以双壳类为模型来测试所有重建祖先特征、年龄和分布的主要方法，这项研究的结果将对基因组学、免疫学和生态学等领域产生深远的影响。作为这一努力的一部分，该项目还将培训从高中到博士后水平的学生，并将广泛传播成果。

This project seeks to develop bivalve molluscs as a preeminent model for evolutionary studies that span long periods of time. Evolutionary family trees (phylogenies) will be constructed for two families of bivalves, the cockles/giant clams and the pitarines, using a combination of DNA sequence data and morphology. These phylogenies will include 200 living and 100-200 extinct species and will be combined with computer simulations and the exceptional bivalve fossil record to test the accuracy of common methods in evolutionary estimation and reconstruction. Specifically, the project will test methods that use data from living species to estimate the ages, physical traits, and geographic distributions of ancestors throughout history. Nearly every aspect of modern comparative biology rests on the assumption that a phylogeny can be used to reconstruct the evolution of a variety of ancestral attributes. But reconstructions based on living species have broad uncertainties because the methods have not been tested against a precise history as represented in the fossil record. The bivalves are ideal for this effort because they are abundant today but also and have a rich fossil record. By using bivalves as a model to test all the major methods of reconstructing ancestral traits, ages, and distributions the results of this research will have far reaching impacts on fields as diverse as genomics, immunology, and ecology. As part of this effort the project will also train students from the high school to postdoctoral levels and will disseminate results broadly.