Announcements

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Announcements

1. Testing center scoring of multiple choice
2. Today overview of a few applications of
   recombinant DNA technology and small group
   discussions of ethics of using this technology
3. Pre-lab questions for behavior lab (lab 13) due
   at start of lab next week

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Southern blot analysis
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RFLPs restriction fragment-length polymorphisms
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Establishing linkage between a dominant trait
and an RFLP allele
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Amniocentesis
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Chorionic Villus Sampling
CVS uses catheter in uterus to obtain fetal
chorion tissue.
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Diagnosis of ?-thalassemia Deletion by Southern
Blotting

• Autosomal recessive, decreased or absent
  ?-globin protein.
• Mutant alleles have large deletions or point
  mutations.

Restriction Enzyme Cut Sites
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Diagnosis of Sickle-Cell Anemia Substitution by
Southern Blotting
Restriction Site Lost in Sickle Allele
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Individuals with Severe Combined Immunodeficiency
(SCID) Have no Functional Immune System
Homozygous for a defective ADA gene in T
cells. Bubble boy, David, lived until removed
from isolation after a bone marrow transplant to
restore his immune system.
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Gene Therapy Involves a Retroviral Expression
Vector, Based on Moloney Murine Leukemia Virus
Genes for viral replication removed
Strong promoter
Long Terminal Repeat regions cause
integration into host genome
Inserted Human Adenosine Deaminase Gene
Infect T cells and return cells to patient.
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Gene Therapy for SCID
Integration into chromosome
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The first patient (SCID) Ashanti de Silva,
treated at 4, is now 15

• Additional Successes Reported in Science (2000)
  288669-672.
• Gene Therapy reviewed in Science (2000)
  288627-629.

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Limits of Gene Therapy

• Circulating cells, e.g. lymphocytes, are easier
  to target than solid tissues.
• Integration of retroviral vectors only in host
  cells replicating their DNA.
• Many vectors illicit an immune response.
• Insertion into genes can inactivate them.
• Vectors can carry a limited amount of DNA.
• New generation vectors are addressing these
  problems.

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Ethics of Gene Therapy

• Somatic Cell Therapy targets diseased cells of
  patient, not passed on to offspring.
• Germ Line Therapy alters germ cells, creates
  heritable change.
• Enhancement Gene Therapy for increased height,
  intelligence

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It would be unfair. Simply rude to create
another race. A mummyfied race with no end. It
would also be surprisingly stupid to even
consider such a thing as to clone an entire
human. We would be creating the " Surpirior Race
" as few like to believe. Leaving God out of it,
we would be create the End of the entire human
race. And Clones WOULD be our End. To imagine
something being created that would have a
learning ability above our own, strength, and
something that could easily become unstoppable,
is by far,unthinkable,and incredibly stupid. They
WOULD evolve into a higher state of life, and
would eventually be uncontrollable, the human
races end. Even to suggest that they would THINK
like us is UNBELIEVABLE!!! Humans have bad
steakes! By cloning something with bad streakes
you'd end up with something with a bad
streak...only smart enough to do whatever they
wanted, and not get stopped. In my
part....cloning parts is okay, but a whole human
clone ....would be wrong.
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My medical ethics students have been discussing
the cloning issue...here are the class thoughts.
Cloning of humans will be used for 2 reasons
Therapeutic and Reproductive Purposes. The
Therapeutic benefit will be a positive and may
lead to cures for parkinsons, alzheimers and
other diseases Reproductive benefit is more of a
social benefit to limited number of
individuals...such as parents wanting to clone a
child who has died. The cloning issue provides a
"slippery slope" ethics that began with Abortion
Ethics in the 70's...which made abortion (killing
of human/potential human life) legal...the moral
issue will never reach closure and
continues...the primary question...when does life
begin and who has rights over this life continue
to be debated from abortion to embryo research to
prenatal diagnosis and continues with the cloning
debate. Our society will continue to create legal
decisions that weigh the benefit of the few
versus the good of the group...what each person
needs to remember is that making a procedure
legal does not make it moral...only you can
decide that!