Phylogeny and Rates of Evolution of the Carnivora (Mammalia)

9707225弗林食肉动物(哺乳纲)对于生物学研究来说是一个极其重要的类群，原因包括：(I)除南极洲外的所有陆块中都有出现，(Ii)在各种陆地和水生生境中作为关键捕食者的地位，(Iii)拥有各种有充分记录的行为(包括社会)、觅食和其他(通常是独特的)适应，以及(Iv)广泛的化石记录。研究人员约翰·弗林和迈克尔·内德巴尔将研究一大批来自食肉动物化石的新的、高质量的头骨和颅后特征，以更好地确定早期食肉动物群体的辐射模式和时间--这将提供一个关键框架，从这个框架出发，现代食肉动物群落之间的多样性和谱系关系。弗林和内德巴尔还将从大约30个具有代表性的食肉动物类群中获取和检查大约12.5万个碱基对的DNA。DNA序列将来自线粒体编码的两个基因和细胞核编码的两个基因。DNA序列将提供一个独立的数据来源，从中可以推断食肉动物之间的系谱关系。最后，弗林和内德巴尔将把每个基因序列映射到支持最好的系谱上，以检验分子变化的假说。具体地说，他们将研究分子变化是随着时间的推移或多或少同质地发生(“分子时钟”理论)，还是变化是间歇性的。这项研究的结果将对食肉动物和分子多样化的过程和模式产生深远的影响。

9707225 Flynn The Carnivora (Mammalia) are an extremely important group for biological studies for several reasons, including (i) occurrence in all land masses except Antarctica, (ii) position as keystone predators in a variety of terrestrial and aquatic habitats, (iii) possession of a broad variety of well-documented behavioral (including social), feeding, and other (often unique) adaptations, and (iv) an extensive fossil record. Investigators John Flynn and Michael Nedbal will examine a large suite of new, high-quality cranial and postcranial characters from fossil carnivorans to better determine the pattern and timing of radiation in early carnivoran groups - this will provide a critical framework from which diversification and genealogical relationships among modern carnivoran assemblages. Flynn and Nedbal also will acquire and examine about 125,000 base pairs of DNA sampled from roughly 30 representative carnivoran taxa. The DNA sequences will come from two genes encoded by the mitochondria and two genes encoded in the nucleus. The DNA sequences will provide an independent data source from which genealogical relationships among Carnivora will be inferred. Finally, Flynn and Nedbal will map each gene sequence onto the best-supported genealogies in order to test hypotheses of molecular change. Specifically, they will examine the issue of whether molecular change occurs more-or-less homogeneously through time (the "molecular-clock" theory) or whether change is episodic. Results from the study will have far-reaching implications relative to the processes and patterns of carnivoran and molecular diversification.