Capturing ongoing diversification: a complete phylogeny of an avian radiation using dense sampling of tips

新热带地区包括中美洲、南美洲和加勒比海地区，是地球上鸟类多样性最高的地区。在新热带地区，大约每三只鸟中就有一只来自一种名为亚热带雀形目的鸟类。亚种在形式和功能上多种多样，是从热带雨林到高山草原和岩石海岸线等栖息地鸟类生活的重要组成部分。这种多样性的起源--物种形成的节奏和模式--已经通过之前由美国国家科学基金会资助的工作进行了研究。然而，这项工作没有包含足够的样本来捕捉最新和正在进行的物种形成事件。这些最近的物种形成事件对进化研究是最关键的，因为它们告诉我们目前新物种形成的地点和原因。高分辨率采样还提供了识别新物种和修订物种分类所需的信息。在这个项目中，调查人员正在对亚种多样性进行完全采样，获得新的有担保的样本，并增加1,548个失踪种群的基因组数据，以解决该种群的物种限制，并为多样性研究提供一个全面的框架。这项工作整合了一个协调一致的计划，在三个服务不足的地理区域：阿巴拉契亚田纳西州、路易斯安那州和得克萨斯州西部以西班牙裔为主的社区招募和留住生物多样性科学方面代表性不足的学生。它包括一个关于K-12级鸟类多样性的新计划，为本科生遗传学专业开发一个关于生物多样性遗传学的专门模块，以及支持研究生和研究生研究人员进行研究。该项目的统一原则是，需要完整抽样的所有亚纲进化单位的系统发展史，以提供系统修订的基础，并提高研究该群体中物种形成和进化的能力。研究人员正在利用采样充分的亚鸣雀类辐射(目前公认的1,323个物种，外加1,875个亚种)来完成两个主要目标。首先，他们正在使用实地工作、现有的基因组资源和历史DNA方法，从该组中所有1548个未采样的分类群(包括所有亚种)中获取基因组数据，并估计完整的、经过时间校准的系统发育。其次，他们正在利用这一系统学在假设检验框架内在属、种和亚种水平上对亚种系统学进行重新评估和修订。由于系统发育包含亚纲的所有谱系分化的信息，甚至是最年轻的类群之间的信息，它为感兴趣的研究人员提供了宝贵的资源，这些信息包括详细的多样化动态、物种形成的模式、在一系列时间尺度上的鸟类进化、分子进化以及物种概念和划界。正在获得的新标本、基因样本和基因组数据也是无价的。总而言之，这项工作及其结果为物种丰富的热带地区提供了一幅高分辨率的图片，该热带地区是地球上主要的生物多样性热点之一。这一奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Neotropical region includes Central and South America and the Caribbean and contains the highest diversity of birds of any region on the planet. Roughly one in three birds in the Neotropics is from a group called the suboscine passerines. The suboscines are diverse in form and function and are an important component of the bird life in habitats ranging from tropical rainforests to alpine grasslands and rocky coastlines. The origins of this diversity – the tempo and mode of species formation – have been studied through prior NSF-funded work. However, this work did not contain sufficient sampling to capture the most recent and ongoing speciation events. These recent speciation events are the most critical for evolutionary research because they tell us about where and why new species are forming currently. High-resolution sampling also provides the information necessary to identify new species and revise species classification. In this project, the investigators are completely sampling suboscine diversity, obtaining new vouchered samples and adding genomic data from 1,548 missing populations in order to resolve the species limits in the group and provide a comprehensive framework for research on diversification. This work integrates a concerted program for recruiting and retaining underrepresented students in biodiversity science in three underserved geographic areas: Appalachian Tennessee, Louisiana, and majority Hispanic communities in west Texas. It involves a new program on avian diversity at the K–12 level, development of a dedicated module on biodiversity genetics for undergraduate Genetics students, and support for graduate and post-graduate researchers to conduct research. The unifying principle of this project is that a completely sampled phylogeny of all suboscine evolutionary units is needed to provide the foundation for systematic revision as well as improved capacity for research on speciation and evolution in the group. The researchers are leveraging the well-sampled suboscine passerine radiation (1,323 currently recognized species, plus 1,875 subspecies) to complete two primary aims. First, they are using field work, existing genomic resources, and historical DNA approaches to obtain genomic data from all 1,548 unsampled taxa, including all subspecies, in the group and estimate a complete, time-calibrated phylogeny. Second, they are using this phylogeny to conduct a re-assessment and revision of suboscine systematics at the genus, species, and subspecies levels within a hypothesis-testing framework. Because the phylogeny contains information on all lineage divergences in suboscines even those between the youngest taxa, it provides an invaluable resource for researchers interested in detailed diversification dynamics, modes of speciation, avian evolution at a range of timescales, molecular evolution, and species concepts and delimitation. The new specimens, genetic samples, and genomic data being obtained are also invaluable. Together, this work and its results are providing a high-resolution picture of how diversity has evolved in a species-rich tropical group that contributes to one of the major biodiversity hotspots on the planet.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.