11
Support structure for genetic material
Support structure for genetic material
22
Making proteins in the RER
Making proteins in the RER
Making copies of humans
Making copies of humans
33
Making copies of cells
Making copies of cells… …
Making copies of
Making copies of genetic material genetic material
44
Making copies of
Making copies of genetic material genetic material
Making copies of
Making copies of genetic material genetic material
55
Combining cellular and DNA replication
Combining cellular and DNA replication
The real deal
The real deal… …mitosis in action mitosis in action
66
Increasing variation in genetic material
Increasing variation in genetic material
Meiosis: making
Meiosis: making gametes for sexual reproduction gametes for sexual reproduction
77
Meiosis 1:
Meiosis 1: the first split the first split… …
Meiosis II: the second split
Meiosis II: the second split… …
88
Making sperm and eggs
Making sperm and eggs… …
When things go wrong during meiosis
When things go wrong during meiosis… …
99
Manipulating the system
Manipulating the system… …
1010
A revolutionary idea in medicine A revolutionary idea in medicine
Today
Today’ ’s medicine tries to support or s medicine tries to support or treat injured tissues and organs.
treat injured tissues and organs.
Stem cells might simply replace Stem cells might simply replace damaged cells or possibly even damaged cells or possibly even
regenerate damaged tissues.
regenerate damaged tissues.
Instead of transplanting organs, we Instead of transplanting organs, we could rebuild and restore the tissue!
could rebuild and restore the tissue!
New possibilities, new questions New possibilities, new questions
In addition to rebuilding tissues, stem cell research could In addition to rebuilding tissues, stem cell research could……
1. Create differentiated tissues for drug testing by the 1. Create differentiated tissues for drug testing by the
pharmaceutical industry, decreasing need for animal pharmaceutical industry, decreasing need for animal experimentation.
experimentation.
2. Provide new knowledge regarding cell differentiation 2. Provide new knowledge regarding cell differentiation
and fate specification, leading to better and fate specification, leading to better understanding of birth defects and cancer.
understanding of birth defects and cancer.
3. Treat many currently incurable
3. Treat many currently incurable conditions, opening newconditions, opening new options for patients left without hope from current options for patients left without hope from current therapeutic regimens.
therapeutic regimens.
4. Substantially reduce costs in health care by decreasing 4. Substantially reduce costs in health care by decreasing
need for expensive surgeries and long term care.
need for expensive surgeries and long term care.
5. Move our society from drug-based interventional 5. Move our society from drug-based interventional
therapy to cellular regenerative therapy.
therapy to cellular regenerative therapy.
1111
What is a stem cell?
What is a stem cell?
ÿ
ÿ self-replicating, unspecialized cells self-replicating, unspecialized cells
ÿÿ capable of generating specialized daughter cell progeny capable of generating specialized daughter cell progeny ÿ plentiful in early embryonic developmentÿ plentiful in early embryonic development
ÿ categorized as ÿ categorized as ““embyronic”embyronic” or or ““adultadult”” varieties varieties ÿ
ÿ possess specific markers enabling identification and lineage possess specific markers enabling identification and lineage ÿ exhibit varying ÿ exhibit varying ““plasticityplasticity”” depending upon environment and depending upon environment and
commitment level commitment level
ÿ capacity for self-renewal decreases with agingÿ capacity for self-renewal decreases with aging
Young, impressionable, and accommodating
Young, impressionable, and accommodating
1212
Stages of commitment: low to high Stages of commitment: low to high
Totipotent
Totipotent:: capable of anycapable of any fate, generating all cell types fate, generating all cell types necessary for the organism necessary for the organism Pluripotent
Pluripotent:: possible cellpossible cell types more restricted, cannot types more restricted, cannot make all tissues required for make all tissues required for development
development Multipotent
Multipotent:: limited to a lowlimited to a low number of specialized cell number of specialized cell types in differentiated tissues types in differentiated tissues
Choices become limited in progression from Choices become limited in progression from
embyronic
embyronic to adult stem cells to adult stem cells
1313 Two sources of stem cells
Two sources of stem cells Embryonic
Embryonic::
Adult Adult::
• • pluripotentpluripotent
• • derived from derived from blastocyst blastocyst stagestage
• live without forming tumors• live without forming tumors
• take cues from environment• take cues from environment
• division into unequal progeny• division into unequal progeny
•• multipotentmultipotent
•• derived from specialized tissuederived from specialized tissue
•• dedicated to replenishing host dedicated to replenishing host
•• less versatile than ES cells less versatile than ES cells
•• autologous autologous cells can be obtained cells can be obtained
Nuclear transfer leads to
Nuclear transfer leads to ““therapeutic cloningtherapeutic cloning
” ”
Current research Current research indicates it should be indicates it should be possible to generate possible to generate cells
cells ex vivoex vivo by by somatic cell fusion to somatic cell fusion to create cells that are create cells that are subsequently subsequently reintroduced to the reintroduced to the patient.
patient.
Limitations Limitations of of somatic cell fusion- somatic cell fusion- derived progeny derived progeny remain to be remain to be determined.
determined.
1414 Genetic modification leading to
Genetic modification leading to ““designer babiesdesigner babies”” Theoretically, it could be
Theoretically, it could be possible to use genetic possible to use genetic engineering to predetermine engineering to predetermine characteristics of
characteristics of individuals, leading to individuals, leading to concern over inappropriate concern over inappropriate use of stem cells.
use of stem cells.
Current limitations in our Current limitations in our understanding of stem cells understanding of stem cells and their development and their development prevents this possibility from prevents this possibility from being realized at the
being realized at the present time.
present time.
1515
The promise of stem cell research The promise of stem cell research
Current medicine
Current medicine is based on drug therapy dominated by is based on drug therapy dominated by antibiotics, chemotherapy, antipsychotic agents, and antibiotics, chemotherapy, antipsychotic agents, and other pharmaceutical interventions.
other pharmaceutical interventions.
Scientific medicine of the future
Scientific medicine of the future will likely be based upon will likely be based upon cellular therapies, focused on repair and
cellular therapies, focused on repair and regeneration
regeneration of tissues by cell transplantation.of tissues by cell transplantation.
Instead of chemically intervening to prevent cell Instead of chemically intervening to prevent cell
malfunction or premature cell death,
malfunction or premature cell death, why notwhy not replace the cells in question
replace the cells in question??
Benefits that will ultimately flow to all humanity from this Benefits that will ultimately flow to all humanity from this
research are immeasurable and revolutionary such research are immeasurable and revolutionary such thatthat
