Part I Chapter 1
-Basic Problems of developmental Biology: • Maintenance of complete genome while cells differentiate
-Main mechanisms of differential gene expression-polarity and cytoplasmic differences; polarity: • Gene expression leads to a difference in cells • Every cell in body has the same genome • Gene regulation occurs: o Polarity and cell division ▪ Uneven egg contents ▪ Environmental factors o Gene cascades o Induction ▪ Cell-cell signaling
-What does development encompass? • Development begins at fertilization • Study of the emergence of living order
-What are the basic questions in developmental biology? 1. Question of differentiation-how can identical genetic instructions produce different types of cells? How can single cell generate so many cells? 2. Question of morphogenesis-how can cells in body organize into functional structures? 3. Question of growth-how do cells know to stop dividing? 4. Question of reproduction-how are germ cells set apart from somatic cells? What instructions are in the nucleus and cytoplasm? 5. Question of regeneration-how do stem cells retain regeneration capacity? Can we harness it to cure diseases? 6. Question of evolution-how do changes in development create new body forms? 7. Question of environmental integration-can environmental chemicals disrupt development? How is development of organism integrated into its habitat?
-Some basics: similarity and relatedness of organisms; development of 3 germ layers: • All develop three germ layers: o Ectoderm- skin, nervous system, brain and nervous system o Endoderm- gut, digestive tract and associated organs, the lungs o Mesoderm- all the rest, kidney blood, heart, gonads, bones, muscles
-History of Embryology-Von Baer’s principles and Haeckel’s misinterpretation; fate mapping and cell lineages: