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Daniel, William L. Moberg, Kirk David 2011-05-07T12:32:06Z 2011-05-07T12:32:06Z 10000-01-01 1989 The superclass Tetrapoda consists of several well defined monophyletic taxa: Anura, Urodela, Gymnophiona, Testudinata, Squamata, Rhychocephalia, Crocodilia, Aves and Mammalia. The relationships among these groups, however, is controversial. Neither paleontological evidence nor morphological, physiological, biochemical or available macromolecular sequence data from living forms has provided a definitive solution. A new data base consisting of 18S and 28S ribosomal RNA sequences was generated. Ribosomal RNA was extracted from liver and mature ova of select tetrapods and directly sequenced using the enzyme reverse transcriptase and deoxy and dideoxynucleotides. Approximately 95% of the 18S and 20% of the 28S were sequenced form twenty tetrapods. In addition, nearly all of the 18S molecule was sequenced from the coelecanth (Latimeria chalumnae). Sequences were aligned and variable sites identified. Four methods of phylogenetic tree construction were employed consisting of (1) least squares distance matrix, (2) maximum parsimony, (3) maximum likelihood and (4) evolutionary parsimony. The effects of character weighting, inclusion or exclusion of taxa, and outgroup choice were also investigated. Analysis of both the 18S and 28S ribosomal RNA sequences were consistent with the monophyly of the Lissamphibia, Anura, Urodela, Amniota, Squamata, Aves and Mammalia. The relationships between these groups including the Testudinata, Gymnophiona and Crocodilia, however, were not resolved. Character weighting, choice of taxa to be included and outgroup choice were shown to affect the tree topology. In addition, separate analyses of the 18S and 28S molecules yielded different tree topologies. Made available in DSpace on 2011-05-07T12:32:06Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 8924900.pdf: 7116698 bytes, checksum: 431d8df138c0d2d837ccda899be22fdf (MD5) Previous issue date: 1989 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:42:18Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:18:23-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI8924900 (UMI)AAI8924900 http://hdl.handle.net/2142/20202 eng Copyright 1989 Moberg, Kirk David Biology, General Biology, Molecular Biology, Zoology Tetrapod phylogeny as inferred from 18S and 28S ribosomal-RNA sequence comparisons text Biology Biology University of Illinois at Urbana-Champaign Dissertation Ph.D.