Presentation on theme: "Comprehending Development: Generating New Cells and Organs"— Presentation transcript:
1Comprehending Development: Generating New Cells and Organs BIOL 370 – Developmental BiologyTopic #1Comprehending Development: Generating New Cells and OrgansLange
2The focus in BIOL 370 – Developmental Biology is to understand the physiological principles that guide development in multicellular organisms.This course will pull information from a wide array of approaches to study biology including….physiology,genetics,anatomy,and cellular biology.V.M. - Amphibian Life Cycle
3Developmental history of the leopard frog, Rana pipiens DevBio9e-Fig jpgEmbryogenesis – the stages of the life cycle from fertilization through hatching (or parturition in mammals).Gametogenesis – the period of time(s) where germ cell lines are in production in some form(Note that in the above, the purple color is showing times of strong germ cell development, whereas the beige is showing times of strong somatic cell development.)
4Heinz Christian Pander Russian biologist, has been credited for the discovery of the three germ layers that form during embryogenesis.Pander received his doctorate in zoology from the University of Wurzburg in 1817.He began his studies in embryology using chicken eggs, which allowed for his discovery of the ectoderm, mesoderm and endoderm.Due to his findings, Pander is sometimes referred to as the "founder of embryology".
5Early development of the frog Xenopus laevis Amplexus – the mating behavioral displayed by frogs where the male will grasp the female around the belly and deposit sperm onto eggs as they are released.Notes:Yolk is in greenAdults matingLaid eggsd – i) Development beyond the fertilized eggDevBio9e-Fig jpg
6Continued development of Xenopus laevis Continued development showing a variety of stages.Note:i) – mature tadpole that has hatched from the eggDevBio9e-Fig jpg
7Metamorphosis of the frog Metamorphosis - biological process by which an animal physically develops after birth or hatching that involves a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation.Various insects, amphibians, molluscs, crustaceans, Cnidarians, echinoderms and tunicates may undergo metamorphosis.Most examples of metamorphosis are also accompanied by a change in habitat and/or behavior.DevBio9e-Fig jpg
8Summary of meiosisIn your review of meiosis, be sure to note the following:Homologus chromosomes - chromosome pairs of the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father. They are not identical, but carry the same type of information.Homologus chromatids - sister chromatids are generated when a single chromosome is replicated into two copies of itself, these copies being called sister chromatids.DevBio9e-Fig (1).jpg
9Summary of meiosisThe resulting production of gametes is the method by which sexually reproducing species produce haploid cells that can be mixed together to create offspring with greater genetic diversity than is seen in asexual reproduction.DevBio9e-Fig (2).jpg
10Depictions of chick developmental anatomy When we examine chick development, we can see a variety of interesting anatomical aspects.DevBio9e-Fig jpg
11Depictions of chick developmental anatomy (Part 1) DevBio9e-Fig R.jpgClassic Drawing by Malpighi (1672)
12Depictions of chick developmental anatomy (Part 2) DevBio9e-Fig R.jpgLillie, 1908
13Depictions of chick developmental anatomy (Part 3) DevBio9e-Fig R.jpgEduard d’Alton
14Depictions of chick developmental anatomy (Part 4) DevBio9e-Fig R.jpg
15Dividing cells of the fertilized egg form three embryonic germ layers As development progresses beyond the zygote and blastula, you see greater differentiation in the gastrula stage.DevBio9e-Fig jpg
16Dividing cells of the fertilized egg form three embryonic germ layers (Part 1) Ectoderm:Differentiates to form the nervous system (spine, peripheral nerves and brain), tooth enamel and the epidermis. It also forms the lining of mouth, anus, nostrils, sweat glands, hair and nails.DevBio9e-Fig R.jpg
17Dividing cells of the fertilized egg form three embryonic germ layers (Part 2) Mesoderm:Forms mesenchyme (connective tissue), mesothelium, blood cells and coelomocytes (immune cells in worms and spiders)Mesothelium lines coeloms; forms the muscles in a process known as myogenesis.DevBio9e-Fig R.jpg
18Dividing cells of the fertilized egg form three embryonic germ layers (Part 3) Endoderm:Parts of the alimentary canal), the lining cells of all the glands which open into the digestive tube, general respiratory tract, the trachea, bronchi, and alveoli, general endocrine glands and organs, parts of the auditory system (the epithelium of the auditory tube and tympanic cavity), urinary system (the urinary bladder and part of the urethra).DevBio9e-Fig R.jpg
19The notochord is an interesting structure that is seen only during embryological development. In early development, it defines the primitive axis of the embryo. In some chordates, it persists throughout life as the main axial support of the body, while in most vertebrates it becomes the nucleus pulposus of the intervertebral disc.
20This image is showing a computer enhanced image of the vertebrate head (in this case a salamander) early in development. The purple colored regions indicate what are called:Pharyngeal Arches(Branchial Arches).In the next slide, look at how these structures develop into various parts of the skeletal bones of the head in different vertebrates.
21Evolution of pharyngeal arch structures in the vertebrate head DevBio9e-Fig jpg
22Notochord in chick development Notochord - guides development of of the nervous system (neural tube/groove)Somites – vertebrae, ribs, skeletal muscle.DevBio9e-Fig jpgAbove – chickTo the right - frog
23Similarities and differences among vertebrate embryos during development DevBio9e-Fig jpg
24Fate Maps and Cell Lineages: Unlike in adults, the cells in the embryo tend to move and shift. Therefore, in developmental biology it is cruicial to identify the following two types of cells:Epithelial cells – cells that are very tightly connected to each other and form sheets of tissue or tubes of tissue.Mesenchymal cells – cells that ARE NOT connected to each other and function as independent units.Fate map for Drosophila sp. eggs.
25Direction and number of cell divisions Morphogenesis – a limited range of variations in processes of a cell within epithelial and mesenchymal cells. Types of morphogenic variations include:Direction and number of cell divisionsversus
26Additional morphogenic variations: Cell shape changesCell migrationsCell growthCell death – (programmed cell death is called apoptosis)Cell membrane changesSecretion changes by cells
31Fate maps of vertebrates at the early gastrula stage Fate Maps – maps of early developmental stages showing a tracing (or map) of cell lineages through developmental time. Important for both descriptive and experimental embryology.DevBio9e-Fig jpg
32Edwin Grant Conklin - traced the formation of organs to their origins in the egg cell and embryo. Conklin also investigated the physical mechanism of cell division.
33Tunicates are marine filter feeders with a sac-like body structure Tunicates are marine filter feeders with a sac-like body structure. In their respiration and feeding they take in water through an incurrent siphon and expel the filtered water through an excurrent siphon.Most adult tunicates are sessile and attached to rocks or similarly suitable surfaces on the ocean floor.Common names for specific examples of species of tunicates include sea squirts, sea pork or sea tulips.
34Fate map of the tunicate embryo This diagram highlights two different ways to represent a fate map…b) Shows a cellular fate mapc) Shows a linear fate mapDevBio9e-Fig jpg
35Walter Vogt - the first "fate map" of a vertebrate embryo -- a description of how cells move from their original positions in the early embryo to their ultimate destination.
36Vital dye staining of amphibian embryos DevBio9e-Fig jpg
37Fate mapping using a fluorescent dye A more modern take on Vogt’s approach:Fluorescence StainingDevBio9e-Fig jpg
38Hilde MangoldEmbryologists who first successfully transplanted embryonic tissues to form chimeric embryos.Hans Spemann
39Chick resulting from transplantation of a trunk neural crest region from an embryo of a pigmented strain of chickens into the same region of an embryo of an unpigmented strainDevBio9e-Fig jpg
40Genetic markers as cell lineage tracers Two more modern takes on ’s Mangold & Spemans’s approach:Genetic MarkersDevBio9e-Fig jpgGenetic Markers
41Fate mapping with transgenic DNA shows that the neural crest is critical in making the bones of the frog jawTransgenic LabelingDevBio9e-Fig jpg
42Larval stages reveal the common ancestry of two crustacean arthropods Similar Appearance Early On Very Different LaterDevBio9e-Fig jpg
43Homologies of structure among human arm, seal forelimb, bird wing, and bat wing DevBio9e-Fig jpg
45Selectable variation through mutations of genes that work during developmental DevBio9e-Fig jpg
46Developmental anomalies caused by genetic mutation Piebaldism - a disorder caused by the KIT gene which regulates production of the KIT protein which guides proliferation and migration of neural crest cells among other cells.DevBio9e-Fig jpgIndividuals affected often experience fertility issues, anemia, underpigmentation of skin and hair, problems with the digestive systems and auditory issues.BE ABLE TO RELATE THIS TO HOW THE NEURALCREST PROLIFERATES INTO THESE REGIONS.
47Developmental anomalies caused by an environmental agent DevBio9e-Fig jpgEnvironmental exposure to chemicals can affect development in a myriad of ways. The gentleman above was exposed to Thalidamide in-utero, and this resulted in his phocomelia (insufficient limb growth).