Zoology 470 Introduction to Animal Development Spring 2015 Jeff Hardin Dept of Zoology 327 Zoology Research phone 262 9634 email jdhardin wisc edu Introduction Why should we care about developmental biology What are the main goals of developmental biology What are the main tools of developmental biology Albert Einstein The most beautiful thing we can experience is the mysterious It is the source of all true art and science He to whom this emotion is a stranger who no longer pauses to wonder and stand rapt in awe is as good as dead http jixifox files wordpress com 2009 12 jixi fox quotable 5 albert einstein jpg Wonder Christopher Hardin 1989 An Old Question Psalm 139 For Thou didst form my inward parts Thou didst weave me in my mother s womb I will give thanks to Thee for I am fearfully and wonderfully made wonderful are Thy works and my soul knows it very well My frame was not hidden from Thee when I was made in secret skillfully wrought in the depths of the earth Thine eyes have seen my unformed substance and in Thy book they were all written the days that were ordained for me when as yet there was not one of them How Do We Study Embryos Observation Yogi Berra You can see lot just by looking Model organisms and technical tools Epigenesis Complexity arises through the interaction of simpler parts Microscopy Antonie van Leeuwenhoek http www britannica com eb art 12567 Antonie vanLeeuwenhoek detail of a portrait by Jan Verkolje Microscopy http micro magnet fsu edu primer museum leeuwenhoek html Leeuwenhoek Microscope http lensonleeuwenhoek net images microscopes scale jpg Microscopy http www nature com nature journal v441 n7096 full 441934a html Preformation Homunculus preformed in sperm Nicolas Hartsoeker 1694 Gilbert 4e Fig 4 1 Big Ideas in Developmental Biology Differentiation How parts become different Morphogenesis Building the body from the Greek form Differentiation The process by which differing properties are conferred on parts of the embryo at different times and in specific locations such that specific structures arise in the mature organism in a reliable fashion the Why question Morphogenesis From the Greek form The study of the mechanisms by which the shape of the embryo arises the How question Dynamic movements of tissues and cells Pattern formation The process by which different regions of an embryo or structure become spatially organized to produce different structures Subsequent morphogenesis and differentiation complete the process How Do We Study Embryos Microsurgery What Do Cells Do In New Situations The Organizer Hans Spemann Hilde Mangold http www bioinfo org cn book Great 20Experments great30 htm The Organizer Dorsal lip of the blastopore Review Fate Mapping Gilbert 10e Fig 1 13 Germ layers Primary tissue layers that ultimately generate all of the major differentiated tissues of the body Higher animal are triploblastic 3 germ layers The three germ layers are ectoderm mesoderm and endoderm Review Germ Layers Gilbert 10e Figure 1 7 Review Germ Layers Gilbert 10e Figure 1 7 Review Germ Layers Gilbert 10e Figure 1 7 Review The Organizer Gilbert 7e Fig 10 21 The Organizer Gilbert 7e Fig 10 21 Induction The process by which one cell or tissue the inducer sends a signal to a second cell or tissue the induced cells resulting in a specific and reproducible change in their differentiation What Do Experiments Tell Us Sufficiency When a group of cells or molecule when added to a cell embryo or tissue confers the ability to differentiate in a particular way Does NOT mean a molecule or group of cells is necessary Example Bill Gates vs the lottery If a cell or molecule is sufficient but not necessary this often indicates functional redundancy What Do Experiments Tell Us Necessity When a group of cells or molecule is removed from a cell embryo or tissue the ability to differentiate in a particular way is lost Does NOT mean a molecule or group is sufficient Example Air and water If something is necessary but not sufficient it indicates it acts together with other essential cells molecules Question Does the Organizer experiment show that the organizer cells are sufficient or necessary for making the primary embryonic axis in amphibians In 2 3 sentences explain your answer Specification The extent to which a cell or tissue will differentiate normally when placed in new surroundings Autonomous vs conditional Autonomous Specification E B Wilson http www columbia edu cu alumni Magazine Fall2002 Wilson html Autonomous Specification Early decisions reproducible divisions E B Wilson mollusks see Gilbert 10e Fig P2 1 Autonomous Specification Often associated with localized determinants Localized determinants can be sufficient necessary or both The Lineage Plan from The Way Life Works Myoplasm is in Muscle Precursors Gilbert 10e Fig 7 22 Autonomous Differentiation in Ascidians Gilbert 10e Fig 1 12 Autonomous Differentiation in Ascidians Isolation Gilbert 8e Fig 3 9 Myoplasm in Ascidians Isolation Gilbert 10e Fig P2 2 Myoplasm Redistribution Gilbert 10e Fig P2 3 Conditional Specification Hans Driesch http www sammlungen hu berlin de dokumente 11742 Conditional Specification Late decisions variable divisions Hans Driesch and sea urchins Gilbert 10e Fig P2 7 Conditional Specification Often associated with regulative development Gilbert 10e Fig P2 7 Conditional Specification DIANE ARBUS IDENTICAL TWINS ROSELLE NEW JERSEY 1967 http carolinebriggs wordpress com 2012 02 12 seeing double Question Are the cells of the Organizer autonomously or conditionally specified at the time the experiment is usually performed In 2 3 sentences explain your answer The Modern Era Model Systems Model systems You can learn a lot about a Mercedes by studying a Toyota Different model systems pick the right tool for the job Model Systems in Developmental Biology courtesy M Hardin December 2014 Model Systems in Developmental Biology Jeff s car Jon s car July 2011 Model Systems Cellular analysis of development Molecular and genetic analysis of development Model Organisms The Cast of Characters Campbell et al Biology 5e Fig 21 3 Drosophila Mus musculus C elegans Danio rerio Zebrafish Imaging Embryos Fluorescence Microscopy http www microscopyu com articles fluorescence fluorescenceintro html Green Fluorescent Protein GFP Nobel Laureates 2008 Roger Tsien Marty Chalfie Osamu Shimomura http www reuters com article topNews idUSTRE4973T620081008 http www giappone360 it 2008 10 10 nobel premio chimica a due americani e