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Phylogeny

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Articles 31 - 40 of 40

Full-Text Articles in Evolution

Evolutionary Relationships Among Duiker Antelope (Bovidae: Cephalophinae), Anne Johnston Dec 2011

Evolutionary Relationships Among Duiker Antelope (Bovidae: Cephalophinae), Anne Johnston

LSU New Orleans Theses and Dissertations

Duikers are a species rich subfamily of threatened African antelope whose recent origin poses a challenge to the molecular identification of taxa and estimation of their phylogeny. I test the ability of DNA barcodes to identify all taxa within this group. I then use mitochondrial and nuclear genes to estimate a multi-locus species tree and to date divergence times. DNA barcodes are unable to distinguish many sister taxa, calling into question the utility of barcodes for the regulation of duiker trade or in identification of field-collected feces. The multi-locus phylogeny provides support for the relationships among major duiker lineages and …

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Episodic Radiations In The Fly Tree Of Life, Brian M. Wiegmann, Michelle D. Trautwein, Isaac S. Winkler, Norman B. Barr, Jung-Wook Kim, Christine Lambkin, Matthew Bertone, Brian Cassel, Keith Bayless, Alysha Heimberg Apr 2011

Episodic Radiations In The Fly Tree Of Life, Brian M. Wiegmann, Michelle D. Trautwein, Isaac S. Winkler, Norman B. Barr, Jung-Wook Kim, Christine Lambkin, Matthew Bertone, Brian Cassel, Keith Bayless, Alysha Heimberg

Dartmouth Scholarship

Flies are one of four superradiations of insects (along with beetles, wasps, and moths) that account for the majority of animal life on Earth. Diptera includes species known for their ubiquity (Musca domestica house fly), their role as pests (Anopheles gambiae malaria mosquito), and their value as model organisms across the biological sciences (Drosophila melanogaster). A resolved phylogeny for flies provides a framework for genomic, developmental, and evolutionary studies by facilitating comparisons across model organisms, yet recent research has suggested that fly relationships have been obscured by multiple episodes of rapid diversification. We provide a phylogenomic …

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Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis Apr 2011

Multilocus And Parametric Analyses Of The Evolutionary History Of The Amazonian Peacock Cichlids, The Genus Cichla (Teleostei: Cichlidae), Stuart Clayton Willis

School of Biological Sciences: Dissertations, Theses, and Student Research

Accurate knowledge of species boundaries and species phylogeny are fundamental to testing hypotheses of recent evolutionary processes, but the estimation of these partitions is challenging due both to inherent confusion about what is being estimated as well as the data available to estimate them. Using multilocus data from mtDNA, microsatellites, and nuclear locus sequences of over 1100 individuals, we delimited eight separately evolving species of Cichla rather than the 15 described. Among species we found evidence of rare but widespread introgressive hybridization, while within these species we observed evidence of long-term gene exchange and constrained evolutionary trajectories. In most cases …

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Evolutionary Genetics Of African Toads (Anura: Bufonidae: Amietophrynus), Nancy P. Conkey^, Eli Greenbaum* Mar 2011

Evolutionary Genetics Of African Toads (Anura: Bufonidae: Amietophrynus), Nancy P. Conkey^, Eli Greenbaum*

COURI Symposium Abstracts, Spring 2011

African "true" toads (frog genus Amietophrynus) include 39 morphologically conserved species that live in a panoply of habitats from the fringes of the Sahara to the mountains of South Africa. We examined the evolutionary relationships of these African bufonids by sequencing a 550 bp fragment of the 16S mitochondrial gene, and based on these results, collected a further 4 kb of combined mitochondrial (12S–16S) and nuclear (CXCR4, POMC, and RAG1) sequence data from sixty-two divergent samples of the genus Amietophrynus, and several bufonid outgroups. DNA sequences were analyzed with maximum parsimony,maximum-likelihood and Bayesian inference with the programs PAUP, RAxML and …

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Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson Nov 2010

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. However, this insight has been obscured by controversy over their interrelationships. Morphological cladistic analyses have identified lampreys and gnathostomes as closest relatives, whereas molecular phylogenetic studies recover a monophyletic Cyclostomata (hagfish and lampreys as closest relatives). Here, we show through deep sequencing of small RNA libraries, coupled with genomic surveys, that Cyclostomata is monophyletic: hagfish and lampreys share 4 unique microRNA families, 15 unique paralogues of more …

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Systematics Of The Genus Ptychadena Boulenger, 1917 (Anura: Ptychadenidae) From Democratic Republic Of The Congo, Katrina Marie Weber Jan 2010

Systematics Of The Genus Ptychadena Boulenger, 1917 (Anura: Ptychadenidae) From Democratic Republic Of The Congo, Katrina Marie Weber

Open Access Theses & Dissertations

This thesis increases the scope of previous phylogenetic analyses that revealed high levels of genetic differentiation within the anuran genus Ptychadena. Herein, I increase sampling of Central African populations of Ptychadena by over six times to examine their relationships to other African populations and to search for cryptic species. This study represents the most comprehensive molecular phylogeny of Ptychadena to date. A total of three mitochondrial (12S, 16S, and cyt b) and two nuclear (RAG1 and rhodopsin) genes were sequenced for 67 specimens of Ptychadena. Maximum parsimony, maximum likelihood, and Bayesian analyses were conducted. These analyses revealed …

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Micrornas And The Advent Of Vertebrate Morphological Complexity, Alysha M. Heimberg, Lorenzo F. Sempere, Vanessa N. Moy, Phillip C. J. Donoghue, Kevin J. Peterson Feb 2008

Micrornas And The Advent Of Vertebrate Morphological Complexity, Alysha M. Heimberg, Lorenzo F. Sempere, Vanessa N. Moy, Phillip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

The causal basis of vertebrate complexity has been sought in genome duplication events (GDEs) that occurred during the emergence of vertebrates, but evidence beyond coincidence is wanting. MicroRNAs (miRNAs) have recently been identified as a viable causal factor in increasing organismal complexity through the action of these ≈22-nt noncoding RNAs in regulating gene expression. Because miRNAs are continuously being added to animalian genomes, and, once integrated into a gene regulatory network, are strongly conserved in primary sequence and rarely secondarily lost, their evolutionary history can be accurately reconstructed. Here, using a combination of Northern analyses and genomic searches, we show …

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Historic Genetic Structuring And Paraphyly Within The Great-Tailed Grackle, Jeffrey M. Dacosta, Walter Wehtje, John Klicka Feb 2008

Historic Genetic Structuring And Paraphyly Within The Great-Tailed Grackle, Jeffrey M. Dacosta, Walter Wehtje, John Klicka

Ornithology Program (HRC)

The Great-tailed Grackle (Quiscalus mexicanus) and Boat-tailed Grackle (Q. major) are sister species that have expanded their ranges during historical times. This expansion has created an area of sympatry between these species in Texas and Louisiana, and between distinctive Great-tailed Grackle subspecies in the southwestern United States and northern Mexico. We investigated the evolutionary histories of both species using mitochondrial DNA sequence data and modern phylogenetic methods. Our results reveal genetic structure within Great-tailed, but not Boat-tailed Grackles. Great-tailed Grackles are separated into two clades, but range expansion in the north has led to secondary contact …

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The Cynipoid Genus Paramblynotus: Revision, Phylogeny, And Historical Biogeography (Hymenoptera, Liopteridae), Zhiwei Liu, Fredrik Ronquist, Goeran Nordlander Jan 2007

The Cynipoid Genus Paramblynotus: Revision, Phylogeny, And Historical Biogeography (Hymenoptera, Liopteridae), Zhiwei Liu, Fredrik Ronquist, Goeran Nordlander

Faculty Research & Creative Activity

The genus Paramblynotus is the most species-rich genus of the so-called macrocynipoids, the large cynipoid parasitoids of wood-boring and cone-boring insect larvae. The species range in size from some of the largest to the smallest macrocynipoids, comparable in size to microcynipoids. Paramblynotus members occur on all continents except Europe and Australia, with most species being tropical or subtropical. The biology is poorly known but a few observations indicate that the species are parasitoids of beetle larvae. In this monographic revision of the genus, we present a species-level cladistic analysis based on qualitative and quantitative features of the external morphology. For …

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Phylogenetic Reanalysis Of Strauch's Osteological Data Set For The Charadriiformes, Philip C. Chu Feb 1995

Phylogenetic Reanalysis Of Strauch's Osteological Data Set For The Charadriiformes, Philip C. Chu

Biology Faculty Publications

Strauch's (1978) compatibility analysis of relationships among the shorebirds (Charadriiformes) was the first study to examine the full range of charadriiform taxa in a reproducible way. Subsequently Mickevich and Parenti (1980) leveled serious charges against Strauch's characters, method of phylogenetic inference, and results. To account for these charges, Strauch's characters were re-examined and recoded, and parsimony analyses were performed on the revised matrix. A parsimony analysis on 74 taxa from the revised matrix yielded 855 shortest trees, each length = 286 and consistency index = 0.385. In each shortest tree there were two major lineages, a lineage of sandpiper-like birds …

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