CDB 325-DB Bootcamp - PowerPoint PPT Presentation

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CDB 325-DB Bootcamp

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  1. CDB 325-DB Bootcamp Goals: Learn the basics on the development of the model organisms used at Vanderbilt. Descriptive embryology (not experimental zoology, developmental biology, genetic manipulation, etc) Care and feeding Compare and contrast Course Management Director: David Bader Student Director: Hillary Hager Student Director (in training): Rachel Skelton Coordinator: Kim Kane Grades There will be a test. Attendance. Asking questions/Participation. Getting into it.

  2. Anatomical Positions Organisms, organ systems, and organs have names for the different surfaces and positions. Next week, use the right terms when you examine embryos.

  3. What “larger” questions in biology are best approached by Developmental Biology? Differentiation Morphogenesis Growth Reproduction Evolution Nature/Nurture how one cell gives rise to many different cell types generation of ordered forms comprised of organized cells regulated cell growth is essential instructions must be passed between generations species diversity with colinearity of mechanism and genes how the environment influences developmental processes

  4. Things don’t always look as they seem. Embryology is a moving target in terms of?? Morphogenesis Cell division and migration Gene expression and cell diversification Reaction with the environment More? One question I have: When do larval forms arise in evolution?

  5. Relationship of embryo and mother There are differences. Any guesses? Number of eggs/ovulation cycle Site of fertilization Site of embryonic development Energy/raw materials Others?

  6. Who is this? Imagine discovering something so fundamental. What discoveries could have challenged this finding? Genetics Molecular Biology Does ontology recapitulate phylogeny?

  7. What are the major stages/events in embryogenesis? Fertilization Cleavage Morula Blastula Gastrulation Partitioning of germ layers Organogenesis Growth Sexual maturation Reproduction Death

  8. The 20th Century Developmental Biology T. Boveri & WS Sutton chromosomal theory-complex structures that differ from one another within the same nucleus, responsible for developmental program. Interactions between nucleus and cytoplasm/ gradient hypothesis N.Sevens and EB Wilson sex chromosomes of insects, correlated nuclear structure (XX,XY or XO) with sexual development TH Morgan X-linked mutations/genetics and development EG Conklin lineage studies of Styela partita H. Spemann surgical manipulation of amphibian embryos, the organizer Wilkins, Watson, Crick (Franklin?) DNA as the genetic material Nusslein-Volhard and Wieshaus Merging genetics, experimental zoology and development What’s next? What do you like is the next great discovery?

  9. Basic Concepts of Experimental Embryology • Homology versus Analogy • evolutionary implications • Fate mapping • the importance of observation • Cell Specification • how cells take on different fates • Gradients • the organization of morphogens

  10. Here are Four HomologousStructures that are Derived from a Common Evolutionary Precursor. There are two pairs of AnalogousStructures that have a Common Function Is this right? 1.13

  11. Basic Concepts of Experimental Embryology • Homology versus Analogy • evolutionary implications • Fate mapping • the importance of observation • Cell Specification • how cells take on different fates • Gradients • the organization of morphogens

  12. Conklin’s study of the Tunicate, Styela partita These fate mapping studies were carried out by direct observation and were facilitated because different cell types are normally pigmented in this organism (the sea squirt) G1.7

  13. Basic Concepts of Experimental Embryology • Homology versus Analogy • evolutionary implications • Fate mapping • the importance of observation • Cell Specification • how cells take on different fates • 4 basic experimental approaches • Gradients • the organization of morphogens

  14. Basic Experimental Approaches to Examine Specification Defect: observe development when one portion of embryo is destroyed (but not removed) Isolation: remove portion of embryo and observe its development Recombination: move one portion of the embryo to another part of the same embryo Transplantation: same as 3. But here move to a DIFFERENT embryo Mas?(I can think of a couple.)

  15. Autonomous Specification/Mosaic Development • Characteristic of most invertebrates • Specification by differential acquisition of cytoplasmic molecules • Invariant cleavage patterns (identical cell lineages) • Blastomeres identical What’s the experiment? What does the outcome mean? • Characteristic of most invertebrates • Specification by differential acquisition of cytoplasmic molecules • Invariant cleavage patterns (identical cell lineages) • Blastomeres identical What is the difference between “cell fate, cell specification and cell lineage”?

  16. Autonomous Specification in Styela each disassociated blastomere pair forms structures they would have become in the embryo isolation 3.8

  17. Conditional Specification • the fate of a cell depends on its position and interactions • removal of cells can be compensated • Massive cell rearrangements and migrations usually occur • Regulative development occurs when interactions that are dependent upon a cell’s neighbors is seen in most vertebrate systems transplantation defect What would the outcome be if this were a mosiac system?

  18. Syncytial Specification (in Drosophila) • Characteristic of most insects where early nuclei share cytoplasm • Specification by interactions between cytoplasmic morphogens • Variable cleavage produce no rigid cell fate for specific nuclei • After cellularization, conditional development usually occurs 3.11

  19. Basic Concepts of Experimental Embryology • Homology versus Analogy • evolutionary implications • Fate mapping • the importance of observation • Cell Specification • how cells take on different fates • Gradients • the organization of morphogens

  20. The Activin Gradient Mechanism G 3.20D

  21. Two Experimental Demonstrations of Activin Gradients The more activin a cell receives the “more” mesodermal the cell fate….

  22. The Paradox of Genetic Equivalence and Cellular Diversity

  23. 3.22 The Stem Cell Concept as a General Theme

  24. 3.22 The stem cell concept as relates to Blood Cell Formation

  25. Nuclear Transplantation in Xenopus (Briggs and King, 1952) G4.5/4.6

  26. Clone Family PhotoAlbum Dolly and Bonnie, 2000 CC amd her nuclear donor “mother” Rainbow Shin et.al. Nature (2002) 415:859 Snuppy and somatic skin cell donor “father” Snuppy’s and her Surrogate Mother Lee et al. Nature (2005) 436:641