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Stem Cells andEmbryonic
Development
How old is this?What is it?
What is this?How old is it?
© Mark Hill, UNSW
Central ethical question surrounding embryonic stem cell
research:
Under what circumstances, if any, can 5-14 day old human embryos be:
1. Created and destroyed (prevented from developing further, then immortalized) for research purposes?
2. Donated as research material as a result of the In Vitro Fertilization procedure?
3. Checked and screened for certain genes then selected for or against?
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
Natural Fertilization
The “Old Fashioned Way”
+ =
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
In the IVF procedure, sperm and eggs “interact” in a dish leading to insemination.They literally swim up to the egg and burrow toward the nucleus.The first one to get there wins, and all others are blocked out.
Male fertility issue: Sometimes sperm cannot latch onto and penetrate the egg. They may choose to have Intra(within)-Cytoplasmic Sperm Injection (ICSI)
Day 1
EmbryonicStemCells
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
Embryonic Development: Fish model
Keller et al. 2008
At what point is it a fetus? • Days 7-14: Uterine implantation• Day 14: Three distinct layers begin to form (no
more pluripotent stem cells)• Days 14-21: Beginning of future nervous system• Days 21-24: Beginning of future face, neck,
mouth, and nose• Weeks 3-8: Beginning of organ formation
This picture is Week 5
• Week 5-8+: Now it’s called a fetus (no consensus on a single timepoint)
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
This cellCan form the
entire human being
This cellCannot form the
entire human being
Fully mature
Symmetric cell division
Asymmetric cell division
1. Self-renews 2. Differentiates
Progenitor cell
Stem cell Stem cell
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
What is stem cell research?
• Understand more about development, aging, disease– Experimental model systems
• Prevent or treat diseases and injuries– Cell-based therapies– Pharmaceutical development
• Includes testing and drug delivery
Spinal cord injury:Example of embryonic stem cell-based therapy
Geron video: http://www.geron.com/grnopc1clearance/
CIRM funding breakdown: Cell Type
CIRM funds many types of Stem Cell Research
Outline of Presentation
• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?
Pre-implantation Genetic Diagnosis• A procedure to see if the baby has a chance of
inheriting genetic diseases• One-two test cells taken from morula stage• The embryo can grow normally if chosen for
implantation• Two techniques:
– Heteroduplex Analysis: DNA is tested for structural abnormalities
– Fluorescence In Situ Hybridization (FISH): Chromosomes are dyed to look for translocations and check the number of chromosomes
Ethics of Pre-implantation Genetic Diagnosis
• If the embryo shows a genetic variation linked with a genetic disease the parents could decide to terminate that pregnancy or not use that embryo
Discuss:
Under what circumstances, if any, can 5-14 day old human embryos be:
1.Created and destroyed (prevented from developing further, then immortalized) for research purposes?
2.Donated as research material as a result of the In Vitro Fertilization procedure?
3.Checked and screened for certain genes then selected for or against?