Browsing by Author "Extavour, Cassandra"

Now showing items 1-20 of 35

    • Ablation of a Single Cell From Eight-cell Embryos of the Amphipod Crustacean Parhyale hawaiensis 

      Nast, Anastasia R.; Extavour, Cassandra G. (MyJove Corporation, 2014)
      The amphipod Parhyale hawaiensis is a small crustacean found in intertidal marine habitats worldwide. Over the past decade, Parhyale has emerged as a promising model organism for laboratory studies of development, providing ...

    • Are we there yet? Tracking the Development of New Model Systems 

      Abzhanov, Arkhat; Extavour, Cassandra; Groover, Andrew; Hodges, Scott A.; Hoekstra, Hopi; Kramer, Elena; Monteiro, Antonia (Elsevier, 2008)
      It is increasingly clear that additional "model" systems are needed to elucidate the genetic and developmental basis of organismal diversity. Whereas model system development previously required enormous investment, recent ...

    • ASGARD: An Open-Access Database of Annotated Transcriptomes for Emerging Model Arthropod Species 

      Zeng, Victor; Extavour, Cassandra G. (Oxford University Press, 2012)
      The increased throughput and decreased cost of next-generation sequencing (NGS) have shifted the bottleneck genomic research from sequencing to annotation, analysis and accessibility. This is particularly challenging for ...

    • BMP signaling is required for the generation of primordial germ cells in an insect 

      Donoughe, Seth T; Nakamura, Taro; Ewen-Campen, Benjamin Scott; Green, D; Henderson, Lory O.; Extavour, Cassandra G. (Proceedings of the National Academy of Sciences, 2014)
      Many model organisms specify germ cells using maternally supplied germ-line determinants. In contrast, mice rely on embryonic cell–cell signaling to induce cells to become germ cells. Molecular evidence for inductive ...

    • A Comprehensive Reference Transcriptome Resource for the Common House Spider Parasteatoda tepidariorum 

      Posnien, Nico; Zeng, Victor; Schwager, Evelyn E.; Pechmann, Matthias; Hilbrant, Maarten; Keefe, Joseph D.; Damen, Wim G. M.; Prpic, Nikola-Michael; McGregor, Alistair P.; Extavour, Cassandra G. (Public Library of Science, 2014)
      Parasteatoda tepidariorum is an increasingly popular model for the study of spider development and the evolution of development more broadly. However, fully understanding the regulation and evolution of P. tepidariorum ...

    • Counting in oogenesis 

      Green, Delbert; Sarikaya, Didem Pelin; Extavour, Cassandra G. (Springer Science + Business Media, 2011)
      The determination of a precise number of cells within a structure and of a precise number of cellular structures within an organ is critical for correct development in animals and plants. However, relatively little is known ...

    • Developmental and Genetic Mechanisms of Ovariole Number Evolution in Drosophila 

      Green, Delbert Andre (2014-06-06)
      The goal of the "Quantitative Trait Gene" (QTG) program is to identify genes and mutations that underlie natural phenotypic variation. My goal with this work was to contribute an additional model to the program: ovariole ...

    • Developmental Gene Discovery in a Hemimetabolous Insect: De Novo Assembly and Annotation of a Transcriptome for the Cricket Gryllus Bimaculatus 

      Zeng, Victor; Ewen-Campen, Benjamin Scott; Horch, Hadley W.; Roth, Siegfried; Mito, Taro; Extavour, Cassandra G. (Public Library of Science, 2013-04-05)
      Most genomic resources available for insects represent the Holometabola, which are insects that undergo complete metamorphosis like beetles and flies. In contrast, the Hemimetabola (direct developing insects), representing ...

    • Distal-less and Dachshund Pattern both Plesiomorphic and Apomorphic Structures in Chelicerates: RNA Interference in the Harvestman Phalangium opilio (Opiliones) 

      Sharma, Prasahant P.; Schwager, Evelyn Elisabeth; Giribet, Gonzalo; Jockusch, Elizabeth L.; Extavour, Cassandra G. (Wiley-Blackwell, 2013-04-08)
      The discovery of genetic mechanisms that can transform a morphological structure from a plesiomorphic (=primitive) state to an apomorphic (=derived) one is a cardinal objective of evolutionary developmental biology. However, ...

    • The Effect of Development and Ecology on the Evolution of Ovary Size in Drosophila 

      Sarikaya, Didem Pelin (2015-05-20)
      How the size of an organ is established and altered during evolution is poorly understood. The ovary of fruit flies of the genus Drosophila serves as an interesting model for understanding organ size evolution, as the ...

    • Evidence against a Germ Plasm in the Milkweed Bug Oncopeltus fasciatus, a Hemimetabolous Insect 

      Ewen-Campen, Benjamin Scott; Jones, Tasmin E. M.; Extavour, Cassandra G. (Company of Biologists, 2013-03-07)
      Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic ...

    • Evolution of the bilaterian germ line: Lineage origin and modulation of specification mechanisms 

      Extavour, Cassandra G. (Oxford University Press (OUP), 2007)
      A key focus of evolutionary developmental biology (evo–devo) in recent years has been to elucidate the evolution of developmental mechanisms as a means of reconstructing the hypothetical last common ancestors of various ...

    • An evolutionary perspective on germ cell specification genes in insects 

      Ewen-Campen, Benjamin Scott (2014-06-06)
      This dissertation investigates the embryonic specification of a specific group of cells: the germ cells. Germ cells, which give rise to sperm and egg, are the only cells in sexually-reproducing animals that directly ...

    • Expression-Linked Patterns of Codon Usage, Amino Acid Frequency, and Protein Length in the Basally Branching Arthropod Parasteatoda tepidariorum 

      Whittle, Carrie; Extavour, Cassandra G. (Oxford University Press (OUP), 2016)
      Spiders belong to the Chelicerata, the most basally branching arthropod subphylum. The common house spider, Parasteatoda tepidariorum, is an emerging model and provides a valuable system to address key questions in molecular ...

    • The fate of isolated blastomeres with respect to germ cell formation in the amphipod crustacean Parhyale hawaiensis 

      Extavour, Cassandra G. (Elsevier, 2005)
      Germ cells may be specified through the localization of germ line determinants to specific cells in early embryogenesis, or by inductive signals from neighboring cells to germ cell precursors in later embryogenesis. Such ...

    • The First Myriapod Genome Sequence Reveals Conservative Arthropod Gene Content and Genome Organisation in the Centipede Strigamia maritima 

      Chipman, Ariel D.; Ferrier, David E. K.; Brena, Carlo; Qu, Jiaxin; Hughes, Daniel S. T.; Schröder, Reinhard; Torres-Oliva, Montserrat; Znassi, Nadia; Jiang, Huaiyang; Almeida, Francisca C.; Alonso, Claudio R.; Apostolou, Zivkos; Aqrawi, Peshtewani; Arthur, Wallace; Barna, Jennifer C. J.; Blankenburg, Kerstin P.; Brites, Daniela; Capella-Gutiérrez, Salvador; Coyle, Marcus; Dearden, Peter K.; Du Pasquier, Louis; Duncan, Elizabeth J.; Ebert, Dieter; Eibner, Cornelius; Erikson, Galina; Evans, Peter D.; Extavour, Cassandra G.; Francisco, Liezl; Gabaldón, Toni; Gillis, William J.; Goodwin-Horn, Elizabeth A.; Green, Jack E.; Griffiths-Jones, Sam; Grimmelikhuijzen, Cornelis J. P.; Gubbala, Sai; Guigó, Roderic; Han, Yi; Hauser, Frank; Havlak, Paul; Hayden, Luke; Helbing, Sophie; Holder, Michael; Hui, Jerome H. L.; Hunn, Julia P.; Hunnekuhl, Vera S.; Jackson, LaRonda; Javaid, Mehwish; Jhangiani, Shalini N.; Jiggins, Francis M.; Jones, Tamsin E.; Kaiser, Tobias S.; Kalra, Divya; Kenny, Nathan J.; Korchina, Viktoriya; Kovar, Christie L.; Kraus, F. Bernhard; Lapraz, François; Lee, Sandra L.; Lv, Jie; Mandapat, Christigale; Manning, Gerard; Mariotti, Marco; Mata, Robert; Mathew, Tittu; Neumann, Tobias; Newsham, Irene; Ngo, Dinh N.; Ninova, Maria; Okwuonu, Geoffrey; Ongeri, Fiona; Palmer, William J.; Patil, Shobha; Patraquim, Pedro; Pham, Christopher; Pu, Ling-Ling; Putman, Nicholas H.; Rabouille, Catherine; Ramos, Olivia Mendivil; Rhodes, Adelaide C.; Robertson, Helen E.; Robertson, Hugh M.; Ronshaugen, Matthew; Rozas, Julio; Saada, Nehad; Sánchez-Gracia, Alejandro; Scherer, Steven E.; Schurko, Andrew M.; Siggens, Kenneth W.; Simmons, DeNard; Stief, Anna; Stolle, Eckart; Telford, Maximilian J.; Tessmar-Raible, Kristin; Thornton, Rebecca; van der Zee, Maurijn; von Haeseler, Arndt; Williams, James M.; Willis, Judith H.; Wu, Yuanqing; Zou, Xiaoyan; Lawson, Daniel; Muzny, Donna M.; Worley, Kim C.; Gibbs, Richard A.; Akam, Michael; Richards, Stephen (Public Library of Science, 2014)
      Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda ...

    • Germ cell selection in genetic mosaics in Drosophila melanogaster 

      Extavour, Cassandra G.; Garcia-Bellido, A. (Proceedings of the National Academy of Sciences, 2001)
      Heritable mutations in the germ line lead to genetically heterogeneous, or mosaic, gonads. Many of the genes used in germ-line development also play roles in somatic development [Saffman, E. E. & Lasko, P. (1999) Cell. ...

    • Gray anatomy: Phylogenetic patterns of somatic gonad structures and reproductive strategies across the Bilateria 

      Extavour, Cassandra G. (Oxford University Press (OUP), 2007)
      The last common ancestor of extant bilaterian animals is often referred to as ‘‘Urbilateria’’. Comparative studies of development in a variety of laboratory animals, both traditional model systems and newer ‘‘emerging’’ ...

    • The Hippo Pathway Regulates Homeostatic Growth of Stem Cell Niche Precursors in the Drosophila Ovary 

      Sarikaya, Didem P.; Extavour, Cassandra G. (Public Library of Science, 2015)
      The Hippo pathway regulates organ size, stem cell proliferation and tumorigenesis in adult organs. Whether the Hippo pathway influences establishment of stem cell niche size to accommodate changes in organ size, however, ...

    • Insect Egg Size and Shape Evolve With Ecology but Not Developmental Rate 

      Church, Samuel; Donoughe, Seth; de Medeiros, Bruno; Extavour, Cassandra (Springer Science and Business Media LLC, 2019-07)
      Over the course of evolution, the size of life changes dramatically. These changes are thought to be explained by developmental, morphological, and ecological pressures. To perform phylogenetic tests of these hypotheses, ...