A: genetics is the study of inheritance, we all know there are certain
characteristics you can inherit from your mom and your dad, and
genetics is basically the study of inheritance. The word genetics comes
from a root word that's gene and gene is actually a unit of inheritance.
So if both your parents have blue eyes and you happen to have blue
eyes that's usually inherited from your parents, or if both of your
parents have brown eyes and you inherit brown eyes then that's where
you got your eyes from. Many different things about us actually happen
through inheritance, not everything but probably at least 50% of what
makes us us comes from inheritance. The other 50% probably comes
from our environment. So genetics is the study of inheritance and
therefore it's the study of genes that cause inheritance.
Q: what do the tools of biotechnology allow you to do, what are some
of the big possibilities that biotechnology provides for the realm of
medicine?
A: In the realm of biotechnology you'll hear the term recombinant DNA
technology, or recombinant technology. Recombinant DNA means the
ability to put new DNA molecules together. Now we talked about
inheritance and genes, genes are made out of a chemical DNA,
basically people call it the molecule of life. Those chemicals when
they're put together define a specific gene that will define whether
someone has brown eyes or blue eyes, or whether they're smart or not
so smart, whether they're tall or short. It will define a lot of those
things. In recombinant DNA you can think of it, when you have a poster
that you put together and you cut and paste little pictures onto the
poster, if you just saw the pictures in the magazines that you took
them from they might not tell the story, but if you put them together
on a poster in a certain way it tells you a story, just like actually you do
on the internet when you have a story to tell, you don't just show a
continuous interview you cut and paste the pieces of an interview
together or a story together to communicate something. Recombinant
DNA is taking pieces of DNA and cutting and pasting it together with
molecular enzymes, very tiny enzymes that come from bacteria and
fungi and different types of organisms that allow DNA molecules to
actually be cut apart and then pasted back together in a particular
sequence. That recombination ability leads to an incredible amount of
new experiments which can lead to knowledge and insight about what
the genes do and how they function.
Q: What are the different types of gene therapy ?
A: In gene therapy, ethicists and people in the field basically
discuss 3 types of gene therapy. One is what we call somatic cell gene therapy,
the example of that is trying to treat a patient with cancer. You try to go
into a single patient and you try to get the genes into the cancer to just
destroy the cancer tissue. So in that situation you're going into the
human body in a single person and you're trying to change the genes
of some tissue like a cancer, or maybe there's an enzyme missing in
the liver and you're trying to put in a new enzyme. That's somatic cell
gene therapy, and currently in the United States those are the only
types of experiments that are allowed to be done in humans.
Because
they're therapeutic experiments and gene marking experiments and
they're done in a very controlled fashion. A big part of those
experiments is making sure that you don't get an accidental type of
gene therapy, and that brings us to a second type of gene therapy,
called germ line gene therapy. Germ line gene therapy has been done
in plants and animals to modify plants and animals so that you modify
the genes so that they're inherited from parent to offspring. Transgenic
mice is the most common example of that, there's been more than a
thousand mice engineered, had new genes put in them usually to study
some disease model. Germ line gene therapy has not been permitted
in human beings and I agree with that, and that would entail taking an
embryo or fertilized egg, modifying the gene in the embryo so that if
you did that in a person, if that person had children, that the children
subsequently would be genetically modified. This is not permitted in the
United States, Western Europe or Japan, all the countries that have
looked at this with expert review bodies have agreed that it's not a wise
thing at this point for human beings to modify the inheritance patterns
of humans. There's agreement that we don't know enough about
human beings and inheritance and evolution to consider changing a
person so that we change humanity downstream. Germ line gene
therapy is not permitted.
There's another class of gene therapy that's
discussed that actually could be either germ line or somatic cell and
that's what we call enhancement gene therapy and that's also not
permitted. Things that would be possible to enhance in humans in
theory is maybe you could develop a gene therapy that could make
muscles stronger, you could make people that could lift weights more
or run faster than Donovan Bailey. Those sorts of experiments are not
permitted. It brings up some dilemmas, you can think of situations
where you're trying to treat a disease but that therapy that's developed
might actually be able to treat a syndrome. My kids laugh at me when I
use the joke of trying to develop a gene therapy for hair loss. There
might be a lot of money in developing a gene therapy for hair loss but
that would be considered an enhancement so people aren't currently
permitted to do such an experiment. But you can think of disfiguring
scarring that could happen where somebody's in a car accident and gets
scarring that destroys half of their scalp and you could have a woman
that's very disfigured and maybe being able to do gene therapy and
grow hair on a damaged or scarred scalp, it might be something that
treats a disfiguring injury. You could think of a lot of experiments or
projects that people are very interested in is trying to treat mental
retardation. For a lot of mental retardation the deficit in intelligence in
some of those people is marginal, and so if you can improve the
intelligence by 10 or 15% the level of functioning and the ability of
those people to function in society is greatly enhanced. So there's a
goal to do that. A lot of early intervention in mental retardation with
that as a goal. If you think about some gene therapy experiments
there might be things you can do in the brain to enhance the ability of
memory to work or intelligence by doing gene therapy in the brain. If
you could do that it would be wonderful we could help cure mental
retardation using that sort of an approach. However it might be that u
that same technology could be used to make people who are already
smart, even smarter. And the question is is that fair, or what kind of
challenge does that bring to society if you can improve intelligence
using some sort of genetic or biologic approach. So those kind of
enhancement experiments are also not permitted in United States
Western Europe and Japan where they have committees for this.
Transcript for Clip 2 -- Gene Therapy:
When you think about gene therapy, there's often a misconception that
people have that somehow we're changing evolution or we're changing
people in some weird way, or some science fiction way--the way you
read about in science fiction books or see on Star Trek. But in actuality
what's happening is you're only going in and changing [the genetic
makeup] in one person or in one tissue in that person. You're not
changing the whole person and you're not changing anything about the
children that person would have. In gene therapy, ethicists and people
in the field have basically discussed three basic types of gene therapy.
One is what we call somatic cell gene therapy. The example of that is
trying to treat a patient with cancer. You try to go into a single patient
and you try to get the genes into a cancer to just destroy the cancer
tissue. So in that situation you're going into the human body in a single
person and you're trying to change the genes in some tissue like a
cancer. Or maybe there's an enzyme missing in the liver and you're
trying to put in a new enzyme. That's somatic cell gene therapy. And
currently in the United States, those are the only types of experiments
that are allowed to be done in humans because they're therapeutic
experiments and gene marking experiments. They're done in a very
controlled fashion. Transcript for Clip 3 -- Arguments for biotech:
If you take kids with a lethal genetic disease that might die an
agonizing death over ten or fifteen years from repeated infections and
die, and compare that to kids whose stem cells have been taken out,
genetically modified and put back into them and seem to be living a
normal life, that's a very powerful argument. If you look at cancer
patients who've failed radiation and chemotherapy and have received
gene therapy and their tumor has regressed and you see that patient
up walking around alive who otherwise would have been dead, that's a
very powerful argument for biotechnology. So it's fairly difficult to see
when you're saving lives and saving children that there's not a very
powerful argument for biotechnology. I think we're just on the very early
cusp of this. It is very much is akin to the computer revolution that's
taken place over the last thirty or forty years, very much akin to the
development of the combustion engine, very much to the development
of the light bulb, except biotechnology has much more profound
potential impact on humanity. There are very complicated issues
coming up however, things like; effects on human life span, effects on
human intelligence, issues like when if ever would humans consider
doing a germ line gene therapy experiment. These are very difficult
things that I don't think we have a lot of answers for right now. More comments from Charles J. Link...
Q: What is genetics?
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Posted March 6, 2001