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Chapter 19 Vocabulary: Totipotent Pluripotent Multipotent Unipotent Somatic cell nuclear transfer Therapeutic cloning Outline 19.1 Process of Development 4 sub-phases Cell division (mitosis) Differentiation (specialization) Pattern formation (body plan orientation) Morphogenesis (body form generation) 19.2 Cell Division Control over cell cycle checkpoints Rapid division following fertilization (cleavage) Formation of blastomeres Speed is allowed by shortening Gap phases 19.3 Cell Differentiation Cell determination commits a cell to a developmental pathway Cytoplasmic determinants Cell to cell interactions (induction) Stem cells – capable of both continual division and differentiation Totipotent Pluripotent Multipotent Unipotent Embryonic stem cells are pluripotent Cultured in a laboratory Promise for regenerative medicine Ethical issues 19.4 Nuclear Reprogramming The more differentiated cells are the harder it is for them to start over. Adult cells can not become totipotent Somatic cell nuclear transfer (Dolly) Egg cell is enucleated DNA from somatic cell is inserted into empty egg cell Stimulation to divide Cell division Implanted into surrogate mother Problems with this approach seem to stem from our inability to successfully rewind molecular clocks Therapeutic cloning Egg cell is enucleated DNA from somatic cell is inserted into empty egg cell Stimulation to divide Stem cells are removed and grown in culture Cultured cells / tissue is transplanted into patient 19.5 Pattern Formation Positional information can regulate gene expression Early in development basic body plan forms by sequential gene activation Dorsal / ventral Anterior / posterior Homeotic genes are master genes for body segment development 19.6 Morphogenesis Morphogenesis is the product of changes in cell structure and behavior Unequal division of cytoplasm Change in cell shape or size Apoptosis Cell migration Important information from this chapter: The different kinds of stem cells are important. (If your class seems open minded this makes for an ideal discussion on stem cell research.) Nuclear reprogramming; specifically SCNT and therapeutic cloning
