Reconsideration of the phylogenetic relationships of the enigmatic Bornean Bristlehead (Pityriasis gymnocephala).
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Animals↗
Biomedical subjects
Joel Cracraft
Publications and source records attributed to Joel Cracraft.
Phylogeny and evo-devo: characters, homology, and the historical analysis of the evolution of development.
The concept of homology continues to attract more and more commentary. In systematic and evolutionary biology the meaning of homology as synapomorphic similarity inherited from a common ancestor has gained wide acceptance over the last three or four decades. In recent years, however, developmental biologists, in particular, have argued for a new approach to, and new definition for, homology that revolves around the desire to make it more process-oriented and more mechanistic. These efforts raise questions about the relationship between developmental and evolutionary biology as well as how the evolution of development is to be studied. It is argued in this paper that this new approach to homology seemingly decouples developmental biology from the study of the evolution of development rather than to facilitate that study. In contrast, applying the notion of historical, phylogenetic homology to developmental data is inherently comparative and therefore evolutionary.
Anatomy, Comparative↗
Phylogeny and diversification of the largest avian radiation.
The order Passeriformes ("perching birds") comprises extant species diversity comparable to that of living mammals. For over a decade, a single phylogenetic hypothesis based on DNA-DNA hybridization has provided the primary framework for numerous comparative analyses of passerine ecological and behavioral evolution and for tests of the causal factors accounting for rapid radiations within the group. We report here a strongly supported phylogenetic tree based on two single-copy nuclear gene sequences for the most complete sampling of passerine families to date. This tree is incongruent with that derived from DNA-DNA hybridization, with half of the nodes from the latter in conflict and over a third of the conflicts significant as assessed under maximum likelihood. Our historical framework suggests multiple waves of passerine dispersal from Australasia into Eurasia, Africa, and the New World, commencing as early as the Eocene, essentially reversing the classical scenario of oscine biogeography. The revised history implied by these data will require reassessment of comparative analyses of passerine diversification and adaptation.
Animals↗
Assessing the passerine "Tapestry": phylogenetic relationships of the Muscicapoidea inferred from nuclear DNA sequences.
This study presents new comparative sequence data from the nuclear RAG-1 gene for an increased taxon sample in order to investigate phylogenetic relationships among a diverse songbird superfamily, the Muscicapoidea, which has variously included the waxwings, silky flycatchers, Palm Chat, dippers, starlings, mockingbirds, thrushes, chats, and Old World flycatchers. At the same time, our results provide a test of the often-cited relationships inferred from the phenetic studies of Sibley and Ahlquist [Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale University Press, New Haven, 1990] using DNA hybridization distances. Nuclear DNA sequences confirm the monophyly of the "core muscicapoid" group, as defined by Barker et al. [Proc. R. Soc. Lond. B 269 (2002) 295] and also support the sister-group relationship of the Sturnidae and Mimidae, on the one hand, and the large-bodied thrushes (Turdini)+the Old World flycatchers and robins, on the other. The results of the phylogenetic analysis allow preliminary inferences about muscicapoid biogeographic history.
Animals↗
Solving a sequencing problem in the vertebrate mitochondrial control region using phylogenetic comparisons.
The mitochondrial control region (mtCR) of the bird-of-paradise, Phonygammus keraudrenii, the Trumpet Manucode, contains a unique arrangement of homopolymers and short tandem repeats. Homopolymers occur within a few hundred bases of each other, trapping sequence information between unsequenceable barriers. A comparative strategy, involving other manucode species, allowed the prediction of primer sites in the inaccessible region. The method is suggested for similar sequencing problems.
Animals↗