09.8.24 1 EVOLUTIONARY DEVELOPMENT ZOO3603C Satomi Kohno Satomi Kohno Ph.D. I got my Ph. D. in Yokohama City University, Japan in 2003. I have worked at Zoology department for 6 years since 2003. This is the first time to have the class in English. Sex determination in American alligator No Sex Chromosomes Temperature dependent sex determination (TSD) 33˚C produces male; 30˚C produces female Sex reverse can be induced by estrogens or environmental contaminants. Sex Determination in Alligators100%100%SexReversal33°C30°CEstrogenTreatment(Estradiol; p,p'-DDD;Dicofol; trans-Nonachlor)09.8.24 2 Estrogen signaling Relating to the sex reverse phenomenon, the estrogen signaling is very interesting.  Comparative Receptor function Steroid hormone receptor is the transcription factor.  Comparing the transactivation of the receptor isolated from different species. -12 -10 -8 -6012345E2E1E3EE2C. RoachFold Induction-12 -10 -8 -6051015E1E2E3EE2DESA. Red-belly TurtleLigand Concentrations [log (M)]Fold Induction-12 -10 -8 -6051015E1E2E3EE2DESA. Red-belly TurtleLigand Concentrations [log (M)]Fold Induction-12 -10 -8 -601234567E1E2E3DESB. MosquitofishLigand Concentrations [log (M)]Fold InductionReporter gene assay for the tansactivation Make receptor protein in the cell line. Transfect the plasmid with HRE (hormone response element) and the reporter gene. Receptor-Ligand Complex Expression Plasmid Reporter Plasmid Luciferase cDNA Transcription Translation Receptor Ligand Endocrine Disruptors  Some chemicals in the environment can alter the endocrine system by mimicking the hormone, changing hormone productions or hormone clearance.  A possible agent to induce the sex-reverse.  Some of endocrine disruptors can bind to steroid hormone receptor. 09.8.24 3 Blood cells  Blood cells can be a interesting genetic materials to investigate the endangered animals, since we can collect them without killing the animals.  Most of steroid receptor can be cloned from the blood cells. If you are interested in our research, you can join our group. Contact to me to set up an interview for the undergraduate research. Pipping American Alligator 09.8.24 4 DEVELOPMENTAL BIOLOGY: THE ANATOMICAL TRADITION Chapter 1 The Questions of Developmental Biology Keeping the functional unit  Single cell to adult organism  A machine is never required to function until built.  Organisms have to use one set of structure while constructing others. 09.8.24 5 Egg to adult; adult to egg  How does the fertilized egg give rise to the adult body?  How does the adult body produce another body? ? ? ? Questions of Developmental Biology  Differentiation  Morphogenesis  Growth  Reproduction  Evolution  Environment Differentiation A single cell to hundreds of different cell types. • How can same set of genetic instructions produce different types of cells? • How can the fertilized egg generate so many different cell types? 09.8.24 6 Questions of Developmental Biology  Morphogenesis  How can the cells form such ordered structures?  Growth  How do our cells know when to stop dividing?  Reproduction  How are the sperm and egg set apart to form the next generation. Questions of Developmental Biology  Evolution  How do changes in development create new body form?  Environmental integration  How do environmental signals alter the development. Approaches to Developmental Biology 09.8.24 7 Approaches to Developmental Biology  Anatomical approaches  Base of all research in developmental biology.  Comparative embryology  Evolutionary embryology  Teratology  Mathematical modeling  Experimental approaches  Genetic approaches The Anatomical Approach Comparative embryology  Oviparity: animals born from eggs  Birds, frogs and most invertebrates  Viviparity: live birth  Placental mammals  Ovoviviperity: producing an egg that hatches inside the body  Certain reptiles and sharks 09.8.24 8 Comparative embryology  Holobrastic cleavage  Entire egg is divided into smaller cells.  Frogs and mammals  Merobrastic cleavage  Part of egg becomes the embryo.  Fish and birds  Blastoderm  Microscopic observation after 1672 Epigenesis and preformation  Epigenesis: An embryo develops progressively from an undifferentiated egg cell de novo.  Preformation: An embryo develops from a complete miniature version of the organism. Three or two distinct region of embryo  Triploblastic animals  Ectoderm  Endoderm  Mesoderm  Diploblastic animals  No mesoderm  Sponges, sea anemones, hydra and jellyfish09.8.24 9 Ectoderm To the epidermis, nervous system and pigment cells. Mesoderm To the kidneys, gonads, muscle, bones, heart and blood cells. Endoderm To the digestive tube and the respiratory system. 09.8.24 10 Nuclear response to stimuli The preformed nuclear instructions include the ability to respond to environmental stimuli in specific way.  Induction  No tissue is able to construct organs by itself. Pharyngeal arches found by Heinrich Rathke  Pharyngeal arches = branchial arches and gill arches  Become gill apparatus in fish  Become jaw and ears in mammals Karl von Baer  The general features appear earlier embryo.  The early embryo of “higher” animal isn’t like the adult of “lower” animal. Since “lower” is already specialized. What species is this? 09.8.24 11 Fate maps of different vertebrate classes at the early gastrula stage How we know these? Dye marking Radioactive labeling Fluorescent dyes Genetic marking Dye staining of amphibian embryos Radioactive labeling Autoradiography = X-ray: Can detect radio active signal Grown in a solution containing radioactive thymidine, which was incorporated into DNA 09.8.24 12 Fate mapping using a fluorescent dye In Zebrafish Befor After Formation of the central nervous system No dilution of signals by the cell divisions Genetic markers as cell lineage tracers Chimeric embryos Quail cells has the different morphology of nucleus. Immuno histo chemistry: detection of the protein using the specific antiboby. Different morphology of heterochromatin Quail: large nuclei Chicken: diffuse nuclei Cell Migration