Essay About Genetic Enhancement And Animal Experiments

Human Growth Hormones
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In general, genetic enhancement refers to the exchange of genetic material intended to
modify nonpathological human traits. The term is commonly used to describe efforts optimize
attributes or capabilities by moving an individual from standard to their peak levels of
performance. With enhancement the goal is to modify genes for the desired task needed to be
accomplished. Gene insertion may be intended to affect a single individual through somatic cell
modification, or it may target the gametes, in which case the resulting effect could be passed on
to succeeding generations.
In a sense, the concept of genetic enhancement is not particularly recent if one considers
genetically engineered drug products used to alter physical traits as genetic enhancements. For
example the Human Growth Hormone (HGH), which before 1985 could be obtained only in
limited quantities from cadaveric pituitary glands, now can be produced using recombinant DNA
technology. When its supply was more limited, HGH was prescribed for children with short
stature caused by classical growth hormone deficiency. However, with the advent of recombinant
DNA manufacturing, some physicians have begun recommending use of HGH for hormone
deficient children who are below normal height.
Animal experiments to date have attempted to improve such traits as growth rate or
muscle mass. Although this research is focused on developing approaches to treating human
diseases and conditions, it is possible that discoveries resulting from this research could be
cosmetically applied to enhance traits rather than correct deficiencies.
Similar discoveries could help delay the aging process. For example, a gene called
MGF (Mechano-growth factor) regulates a naturally occurring hormone produced after exercise
that stimulates muscle production. Levels of MGF fall as we age, which the is reason why
muscle mass is lost as we grow older. A treatment to build up muscles would allow us to remain
able-bodied and independent much longer. IGF-1, another muscle-building hormone, has
produced increased muscle mass in laboratory mice. Theoretically, gene insertion of IGF-1 could
produce an equally impressive effect in humans.
Efforts to genetically improve the growth of swine have involved the insertion of
transgenes encoding growth hormone. Nevertheless, despite the fact that growth hormone
transgenes are expressed well in swine, increased growth does not occur. Another effort aimed to
enhance muscle mass in cattle. When gene transfer was accomplished, the transgenic calf
initially exhibited muscle hypertrophy, but muscle degeneration and wasting soon followed and
the animal had to be destroyed.
Gene transfer at the embryonic stage through a technique called pronuclear
microinjection is another approach being tested in animals. However, current knowledge from
animal experiments suggests that embryo gene transfer is unsafe, as its use results in random
integration of donor DNA, a lack of control of the number of gene copies inserted, significant
rearrangements of host genetic material, and a 5 to 10 percent frequency of insertional
mutagenesis. In addition, this technique would necessarily be followed by nuclear transfer into
enucleated oocytes, a process that in at least two animal models is associated with a low birth
rate and a very high rate of late pregnancy loss or newborn death. This is why many believe that
the use of gene transfer at the embryonic stage for enhancement would reach far beyond the
limits of acceptable medical intervention.
Greater success has been achieved in genetic enhancement of plants, which are more
easily manipulated genetically and reproductively. However, the state of knowledge in humans
and other complex organisms does not allow for the controlled genetic modification of even
simple phenotypes.
For example, in humans, for whom more complex traits such as intelligence or behavior
are concerned, the limitations are more pronounced. The genome provides only a blueprint for
formation of the brain. The complex and subtle details of assembly and intellectual development
involve more than direct genetic control and are subject to inestimable environmental influences.
Despite the technical limitations, it is possible that eventually enhancements using techniques
initially intended to restore deficiencies could be redirected to improve memory and problem-
solving, reduce the need for sleep, increase musical capacity, attain desirable personality traits,
protect against cardiovascular disease or cancer, or increase longevity.
Ethical issues
Genetic enhancement raises a host of ethical, legal and social questions. What is meant
by normal? When is a genetic intervention “enhancing” or “therapeutic?” How should the benefit
from a genetic enhancement be calculated