Support structure for genetic material

Transcription

1 Support structure for genetic material 1

2 Making proteins in the RER Making copies of humans 2

3 Making copies of cells Making copies of genetic material 3

4 Making copies of genetic material Making copies of genetic material 4

5 Combining cellular and DNA replication The real deal deal mitosis in action 5

6 Increasing variation in genetic material Meiosis: making gametes for sexual reproduction 6

7 Meiosis 1: the first split split Meiosis II: the second split split 7

8 Making sperm and eggs eggs When things go wrong during meiosis meiosis 8

9 Manipulating the system system 9

10 A revolutionary idea in medicine Today s s medicine tries to support or treat injured tissues and organs. Stem cells might simply replace damaged cells or possibly even regenerate damaged tissues. Instead of transplanting organs, we could rebuild and restore the tissue! New possibilities, new questions In addition to rebuilding tissues, stem cell research could 1. Create differentiated tissues for drug testing by the pharmaceutical industry, decreasing need for animal experimentation. 2. Provide new knowledge regarding cell differentiation and fate specification, leading to better understanding of birth defects and cancer. 3. Treat many currently incurable conditions, opening new options for patients left without hope from current therapeutic regimens. 4. Substantially reduce costs in health care by decreasing need for expensive surgeries and long term care. 5. Move our society from drug-based interventional therapy to cellular regenerative therapy. 10

11 What is a stem cell? self-replicating, unspecialized cells capable of generating specialized daughter cell progeny plentiful in early embryonic development capacity for self-renewal decreases with aging categorized as embyronic or adult varieties possess specific markers enabling identification and lineage exhibit varying plasticity depending upon environment and commitment level Young, impressionable, and accommodating 11

12 Stages of commitment: low to high Totipotent: capable of any fate, generating all cell types necessary for the organism Pluripotent: possible cell types more restricted, cannot make all tissues required for development Multipotent: limited to a low number of specialized cell types in differentiated tissues Choices become limited in progression from embyronic to adult stem cells 12

13 Two sources of stem cells Embryonic: Embryonic: pluripotent derived from blastocyst stage live without forming tumors take cues from environment division into unequal progeny Adult: Adult: multipotent derived from specialized tissue dedicated to replenishing host less versatile than ES cells autologous cells can be obtained Nuclear transfer leads to therapeutic cloning Current research indicates it should be possible to generate cells ex vivo by somatic cell fusion to create cells that are subsequently reintroduced to the patient. Limitations of somatic cell fusionderived progeny remain to be determined. 13

14 Genetic modification leading to designer babies babies Theoretically, it could be possible to use genetic engineering to predetermine characteristics of individuals, leading to concern over inappropriate use of stem cells. Current limitations in our understanding of stem cells and their development prevents this possibility from being realized at the present time. 14

15 The promise of stem cell research Current medicine is based on drug therapy dominated by antibiotics, chemotherapy, antipsychotic agents, and other pharmaceutical interventions. Scientific medicine of the future will likely be based upon cellular therapies, focused on repair and regeneration of tissues by cell transplantation. Instead of chemically intervening to prevent cell malfunction or premature cell death, why not replace the cells in question? Benefits that will ultimately flow to all humanity from this research are immeasurable and revolutionary such that stem cell research must be allowed to proceed. Stem cell research: a matter of life and death? 15