DISSERTATION RESEARCH: The Phylogeny of Poison Dart Frogs (Anura: Dendrobatidae)

美国自然历史博物馆的达雷尔·弗罗斯特博士和塔兰·格兰特先生获得了一项拨款，用于研究毒镖蛙的进化关系。毒镖蛙是来自中美洲和南美洲的一个由200多种物种组成的家族。过去40年的调查使人们对这些青蛙生物学的许多方面有了详细的了解。相比之下，在了解它们的系统发育方面进展甚微，这是对已取得的许多发现进行预测性解释的最低要求。这项研究将对大约100种毒镖蛙及其近亲的线粒体和核DNA序列、形态、皮肤毒素、行为和发声等证据进行系统发育分析。由此产生的系统发育将被用来检验关于毒性进化、栖息地偏好、发声和形态多样化的假说。通过指出生物碱的潜在来源，系统发展图也将有助于指导天然产物化学家。在许多毒镖蛙皮肤中发现的各种剧毒生物碱被用于生物医学研究，对社会有明显的好处。鉴于大多数生物碱的饮食来源仍然是个谜，已知和新化合物的唯一来源是青蛙。获取和分析所有种类的毒镖蛙样本的成本高得令人望而却步，但由于隔离生物碱的能力是一种进化的属性，因此发现一个未经测试的物种嵌套在一组拥有生物碱的物种中，这一发现提供了一个预测，即未测试的物种也可能拥有生物碱。此外，有几种树栖动物受到了严重威胁。对树形目昆虫系统发育的了解将使政策制定者能够设计保护策略，不仅保护已知的有毒物种，还保护任何尚未经过检测的近亲物种。

A grant has been awarded to Dr. Darrel Frost and Mr. Taran Grant of the AmericanMuseum of Natural History to study the evolutionary relationships of poison dart frogs, a family of over 200 species from Central and South America. Investigations over the past 40 years have led to detailed knowledge of many aspects of the biology of these frogs. In contrast, little progress has been made in understanding their phylogeny, which is a minimal requirement for a predictive interpretation of the many discoveries that have been made. This study will undertake a phylogenetic analysis of evidence from mitochondrial and nuclear DNA sequences, morphology, skin toxins, behavior, and vocalizations for approximately 100 species of poison dart frogs and their relatives. The resulting phylogeny will be used to test hypotheses about the evolution of toxicity, habitat preference, vocalizations, and morphological diversification. The phylogeny will also serve to guide natural products chemists by indicating potential sources of alkaloids. The diverse, powerfully toxic alkaloids found in the skin of many poison dart frogs are employed in biomedical research with clear benefits to society. Given that the dietary source of most of these alkaloids remains a mystery, the only source of both known and novel compounds is the frogs. Obtaining and analyzing samples of all species of poison dart frogs is prohibitively costly, but, because the ability to sequester alkaloids is an evolved attribute, the discovery that an untested species is nested within a group of alkaloid-possessing species provides a prediction that the untested species may also possess alkaloids. Furthermore, several species of dendrobatids are critically threatened. Knowledge of dendrobatid phylogeny will allow policy makers to design conservation strategies to protect not only those species known to be toxic, but also any close relatives that have not yet been tested.