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、南美洲和加勒比地区，是地球上鸟类多样性最高的地区。在新热带地区，大约有三分之一的鸟类来自一种叫做亚种雀形目的鸟类。从热带雨林到高山草原，再到多岩石的海岸线，亚鳍的形态和功能多样，是鸟类生活的重要组成部分。这种多样性的起源——物种形成的速度和模式——已经通过先前nsf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近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至关重要，因为它们告诉我们目前新物种在哪里以及为什么形成。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，研究人员对水下生物多样性进行了全面采样，获得了新的担保样本，并增加了1548个缺失种群的基因组数据，以解决该群体的物种限制，为多样化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项目，在三个服务不足的地理区域招募和留住代表性不足的生物多样性科学学生：阿巴拉契亚田纳西州、路易斯安那州和西德克萨斯州的西班牙裔社区。它包括一个在K-12阶段的关于鸟类多样性的新项目，为本科遗传学学生开发一个专门的生物多样性遗传学模块，并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，需要对所有亚纲进化单位进行完整的系统发育采样，以提供系统修订的基础，并提高研究该群体物种形成和进化的能力。研究人员正在利用采样良好的水下雀形目动物辐射（1323种目前已知的物种，加上1875种亚种）来完成两个主要目标。首先，他们利用野外工作、现有的基因组资源和历史DNA方法，从所有1,548个未采样的分类群（包括所有亚种）中获得基因组数据，并估计出一个完整的、经过时间校准的系统发育。其次，他们利用这种系统发育在假设检验框架内对属、种和亚种水平的亚种系统进行重新评估和修订。由于系统发育学包含亚亚纲所有谱系分化的信息，甚至包括最年轻分类群之间的信息，它为研究人员提供了宝贵的资源，这些研究人员对详细的多样化动力学、物种形成模式、鸟类在一定时间尺度上的进化、分子进化、物种概念和划分感兴趣。获得的新标本、遗传样本和基因组数据也非常宝贵。总之，这项工作及其结果提供了一幅高分辨率的图片，展示了一个物种丰富的热带群体的多样性是如何进化的，这个群体是地球上主要的生物多样性热点之一。该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知识价值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.