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#720 - Engineering Humans -- Part 1, 14-Mar-2001

by Rachel Massey*

Inheritable characteristics are passed from one generation to the
next through DNA, a molecule that is present in all of our cells.
Scientists think of DNA as being divided into genes, or units of
genetic information. In the past three decades, scientists have
learned how to mix and match characteristics among unrelated
creatures by moving genes from one creature to another. This is
called "genetic engineering."

As we saw in our series on genetic engineering of food crops,
genetic "engineers" are now moving genes around among plants,
animals, and bacteria on a regular basis, but with very little
understanding of the possible consequences, and almost no safety
testing. Now genetic engineers are starting to modify the genes
of humans, using three approaches: 1) cloning, 2) somatic cell
manipulation, and 3) human germline manipulation.

Cloning: Cloning uses the DNA of an existing individual to create
a new individual. The best-known example is Dolly, a sheep that
was cloned using DNA from a sheep that had been dead for six
years. A human has not yet been cloned, but a team of researchers
including an American and an Italian recently announced they are
going to attempt it.[1]

Somatic cell manipulation: Somatic cells are all the cells of the
body that do not pass DNA on to the next generation. Somatic cell
manipulation is currently practiced in some medical research
centers under the name "gene therapy." For example, researchers
are experimenting with ways to introduce genes into the blood
cells of patients with hemophilia (a blood disorder), and into
cells of the immune system in patients with Severe Combined
Immune Deficiency (SCID), a rare inherited disorder of the immune
system. The idea is to "correct" the genetic component of the
disease instead of, or in addition to, treating the disease with
drugs. Hundreds of trials have been carried out, but in most
cases the patients have not been cured.[2]

Germline manipulation: Germ cells (sperm and eggs) do pass DNA
from one generation to the next. Germline manipulation refers to
changes in the germ cells changes which will be inherited by
successive generations. Designing future generations through
germline manipulation is still in the realm of science fiction,
but just barely: some influential scientists are arguing that it
should be attempted.

Why are scientists pursuing these techniques? Some researchers
see somatic cell manipulation as a promising way to treat serious
diseases, such as cystic fibrosis. Other genetic engineers may
have less idealistic motives. Engineering human cells is
technically appealing, and the mere fact that we possess this
technology is, for some people, sufficient reason to use it. Some
technological optimists are fascinated by the idea of germline
engineering as a way to "take evolution into our own hands" by
redesigning the genetic information in our children's cells.

Engineering human cells could also be a big money-maker. For
example, one company hopes to create a market in "organ repair"
generating cloned cells and tissues to insert into existing
people's organs.[3, pg. 18] Other companies and researchers
simply want to keep open the option to engineer human cells
because it could be profitable in the future, even if they have
not made investments in doing it right now.[3]


There are two main applications of cloning. One is "embryo
cloning," which could be used to create new human parts. For
example, some scientists are working on methods to produce a new
embryo from an existing person's cells and then use the cells
from that embryo to produce replacements for failing body parts
in the original person.[4] An embryo develops about a week after
conception, and in its early stages consists of a few identical

"Reproductive cloning" would produce complete cloned individuals,
like Dolly the sheep. Genetic engineers are now able to clone
mice and cattle as well as sheep.[5, pg. 45] Human cloning would
produce a new person who is a near genetic copy of another
person. He or she would, however, be different from the original
person because he or she would develop in a different environment
and have different experiences.

Many people think both "reproductive cloning" and "embryo
cloning" are repugnant and unethical. Other people think embryo
cloning could be acceptable in some cases to treat disease but
think reproductive cloning is wholly unnecessary and never

In the U.S., federal funds cannot be used for reproductive
cloning experiments and some states have outlawed it, but there
is no federal law against it.[5, pg. 4] A team of researchers
recently announced they are going to attempt human cloning in an
"unidentified Mediterranean country."[1] These researchers have
been widely condemned, but some of their colleagues are primarily
concerned that this early attempt at cloning could give the
technology a bad name and reduce the public's willingness to
allow further cloning research.

Somatic cell manipulation

Somatic cell manipulation adds genes to existing cells in some
part of the human body, such as the lungs or the blood. Somatic
cell manipulation is only supposed to affect the DNA of the
person undergoing the treatment. In theory, it does not produce
changes that could be passed on to that person's children and

Somatic cell manipulation was first attempted on humans in
1990.[6, pg. 110] The mechanisms of somatic cell manipulation are
poorly understood, and the effects can be lethal. In one case, a
teenager died after researchers at the University of Pennsylvania
tried to introduce genes into his liver cells, using a modified
virus to carry the genes to their destination. The idea was that
the virus would "infect" the target cells and insert the desired
genes, without being dangerous itself. The researchers are still
not certain how they killed their patient, but evidence suggests
the virus invaded many organs besides the liver and triggered a
severe immune reaction.[7]

According to the U.S. Food and Drug Administration (FDA), somatic
cell manipulation also poses the threat of insertional
mutagenesis, in which inserting new DNA changes or disrupts the
functioning of existing DNA. (See REHN #716. ) FDA also says
researchers attempting to alter somatic cells could inadvertently
introduce foreign genes into the patient's sperm or egg cells.[8,
pg. 4689] If this happened, researchers could accidentally change
the genetic information passed from parent to child.

Researchers are required to submit data to FDA and the
National Institutes of Health (NIH) on any adverse effects that
occur during somatic cell manipulation trials. After the
teenager's death at the University of Pennsylvania, an
investigation revealed that many researchers were not reporting
adverse effects to NIH, which can make the information public.
Some researchers say it would "confuse people" to report every
death that occurs during these trials because many participants
are seriously ill and could die for reasons unrelated to the

Right now, most information that researchers submit to FDA on
somatic cell manipulation experiments is kept secret.[8, pg.
4688] The agency has issued proposed regulations under which
information about somatic cell manipulation trials will be made
available to the public, and is accepting comments on the
proposed regulations until April 18, 2001.[10]

Germline manipulation

Germline manipulation permanently changes the inheritable
characteristics passed from one generation to the next. This can
be done by altering sperm or egg cells or by altering an embryo.
If an engineered embryo survives and develops into a baby, the
changes introduced by germline manipulation will be present in
every cell of that baby. If the baby survives to adulthood and
has children, the changes will be passed on to future
generations, through that person's sperm or egg cells.

Some researchers try to justify germline manipulation by saying
it could remove or replace DNA associated with an inherited
disease. This is a far-fetched idea and unnecessary; even if both
members of a couple have the genes for a hereditary disease,
there are other ways to produce a child without the disease,
including using donated sperm or eggs. Other researchers say they
want to use germline engineering to give a baby new genetic
features it could not have gotten from its parents. This goal
cannot be achieved through any other technology. It is also a
goal that, by definition, could never be medically necessary
because it would not serve to relieve sickness in an existing
person. Instead, it would aim to "improve" future generations of
human beings.[6, pg. 113]

The attempt to "improve" the human race genetically -- as one
might create a specialized breed of horses or dogs -- is known as
eugenics. In the early decades of the 20th century, eugenics
projects in the U.S. led to forced sterilization of some people
who were considered to have undesirable traits. This included
prison inmates who were considered to be "hereditary criminals."
One forced sterilization was justified by describing a man as
"subnormal mentally," with "every appearance and indication of
immorality."[6, pgs. 20-21] In Nazi Germany, the systematic
extermination of Jews and other people was one part of a eugenic
project to breed a "superior race."[6, pg. 17]

Some prominent scientists hope to achieve eugenic goals through
genetic engineering instead of through breeding. Molecular
biologist Daniel Koshland, formerly the editor of SCIENCE
magazine, argues that "if a child destined to have a permanently
low IQ could be cured by replacing a gene, would anyone really
argue against that?" He continues, "It is a short step from that
decision to improving a normal IQ. Is there an argument against
making superior individuals?... As society gets more complex,
perhaps it must select for individuals more capable of coping
with its complex problems."[4, pgs. 115-116]

To be continued.


*Rachel Massey is a consultant to Environmental Research

[1] Jane Barrett, "U.S., Italian Experts Plan to Clone Humans,"
Reuters (March 9, 2001). Available at

[2] Larry Thompson, "Human Gene Therapy: Harsh Lessons, High
Hopes," FDA CONSUMER MAGAZINE (September-October 2000) Available
at http://www.fda.gov/fdac/features/2000/500_gene.html

[3] See Sarah Sexton, "If Cloning is the Answer, What was the
Question?: Power and Decision-Making in the Geneticisation of
Health," THE CORNERHOUSE Briefing 16 (1999). Available at

[4] Emma Young, "Stem Cell Go-Ahead," NEW SCIENTIST ONLINE
(December 20, 2000). Available at

[5] Margaret Talbot, "The Cloning Mission: A Desire to
Duplicate," NEW YORK TIMES MAGAZINE (February 4, 2001), pgs.
40-45, 67-68.

[6] Ruth Hubbard and Elijah Wald, EXPLODING THE GENE MYTH: HOW
ENFORCERS [ISBN 0807004316]. (Boston: Beacon Press, 1999).

[7] Eliot Marshall, "Gene Therapy Death Prompts Review of
Adenovirus Vector," SCIENCE Vol. 286, No. 5448 (December 17,
1999), pgs. 2244-2245.

[8] Food and Drug Administration, "Availability for Public
Disclosure and Submission to FDA for Public Disclosure of Certain
Data and Information Related to Human Gene Therapy or Xeno-
transplantation," FEDERAL REGISTER Vol. 66, No. 12 (January 18,
2001), pgs. 4688-4706. Available at http://frwebgate.access.gpo.gov/cgi-

[9] Maggie Fox, "Gene Therapy Under Fire," Reuters (January 31,
2000). Available at http://www.abcnews.go.com/sections/living/

[10] See Council for Responsible Genetics Alert, "Tell the FDA
that the Public has a Right to Know about Xenotransplantation and
Gene Therapy, February 28, 2001." Available at

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