Molecular phylogeny of the Drosophila melanogaster species group, with special emphasis on the montium subgroup.
Item
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Title
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Molecular phylogeny of the Drosophila melanogaster species group, with special emphasis on the montium subgroup.
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Identifier
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AAI9986374
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identifier
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9986374
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Creator
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Schawaroch, Valerie Ann.
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Contributor
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Adviser: Gail M. Simmons
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Date
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2000
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Entomology | Biology, Molecular
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Abstract
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Drosophilids, most notably Drosophila melanogaster, are the most well studied and understood eukaryotic organisms in genetics; however, the taxonomic relationships of Drosophilids are poorly understood. Drosophila melanogaster is one of 174 species + 3 subspecies in the melanogaster species group. Recently (Ashburner et al. (1984), Pelandakis et al. (1991) and Pelandakis and Solignac (1993) proposed for 8 of the 12 species subgroups within the melanogaster species group three major unresolved lineages: the ananassae subgroup, the montium subgroup, and the melanogaster + Oriental subgroups. The Oriental subgroups are the elegans, eugracilis, ficusphila, suzukii, and takahashii subgroups. This dissertation employs a cladistic analysis of DNA sequence data in an effort to resolve relationships within the melanogaster species group and its largest species subgroup--- montium that contains 87 species.;Initially, 5 different gene regions (alcohol dehydrogenases [ Adh], cytochrome oxidase II [co ii], hunchback [ hb], 28S ribosomal DNA and 16S ribosornal DNA) were explored for their phylogenetic utility in 24 taxa. Aspects of the data such as relative amount of nucleotide bases, transitions, transversions or different codon positions were tested. A priori evaluation of a gene region's phylogenetic utility seems impossible. Therefore, three gene regions (Adh, co ii , and hb) were chosen because they produced the greatest number of phylogenetically informative characters. A simultaneous analysis produced a single, well-resolved phylogeny for 49 taxa. Of the eight subgroups tested, five contained more than one representative. Monophyly was supported for the ananassae, melanogaster, montium and takahashii subgroups. The suzukii subgroup, whose monophyly has been questioned (Bock and Wheeler, 1972; Bock, 1980; Toda, 1991), was polyphyletic. My dissertation found morphological characters corroborating possible complexes within the takahashii subgroup, polyphyletic affiliations of the suzukii subgroup and the sister relationship of the ananasse + montium subgroups. Many of species relationships within the montium subgroup do not agree with previous established complex affiliations. However, Africa appears to be a region of secondary radiation.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
