Edited & published by
) on Nov 9, 2009
The human body is not perfect. Some are created with inherent faults and ot
hers break down before
their time. Science has the potential to make good these problems by altering how humans are made.
This is genetic engineering, and this article looks at the pros and cons of the technology in humans
Definition of Genetic Engineering
This is part one of a two
part series. Here I will look at a defintion of
and the pros
of human genetic engineering. In
the cons and the ethics of human genetic engineering are
Before weighing up the pros and cons of genetic engineering in humans, it's worth taking the time to
what is meant by the idea. Simply put, it's a way of manipulating our genes in such a
way as to make our bodies better. This alteration of a genome could take place in the sperm and egg
cells. This is known as germline gene therapy and would alter the tra
its that a child is born with. The
changes would be inheritable and passed down through the generations. It is currently illegal in many
The other way to change our genome is to swap our bad genes for good ones
in cells other than the
s. This is known as somatic cell gene therapy. This is where a functioning gene could be fired
into our bodies on a viral vector to carry out the functions that a faulty gene is unable to. This
technology is permitted, though it has enjoyed a very limited
success rate so far (largely because it is
technically very difficult). Nonetheless, it still holds out a great deal of promise.
Pros of Genetic Engineering in Humans
There are many potential advantages to being able to alter the cells in our bodies geneti
To make disease a thing of the past
Most people on the planet die of disease or have family members that do. Very few of us will just pop
up to bed one night and gently close our eyes for the last time. Our genomes are not as robust as we
them to be and genetic mutations either directly cause a disease such as Cystic fibrosis, or
they contribute to it greatly i.e. Alzheimer's. Or in the case of some conditions such as the heart disease
can make our bodies more susceptible to attack from viruses or
our own immune system. If the full benefits of gene therapy are ever realised we can replace the dud
genes with correctly fu
To extend life spans
Having enjoyed life, most of us want to cling on to it for as long as possible. The genetic engineering
of humans has the potential to greatly increase our life spans. Some estimates reckon that 100
years could be
the norm. Of course
for a fatal condition will increase the lifespan of the
patient but we're also talking about genetic modifications of healthy people t
o give them a longer life.
Once we fully understand the genetics of ageing it may be possible to slow down or reverse some of
the cellular mechanisms that lead to our decline
for example by preventing telomeres at the ends of
chromosomes from shortening.
Telomere shortening is known to contribute to cell senescence.
The knowledge gained by working out genetic solutions for the above could help with the design of
better pharmaceutical products that are able to target specifically gen
etic mutations in each individual.
The Cons of Human Genetic Engineerin
of this article looked at the pros of genetic engineering in humans. Now, we look at the cons.
As with any new technology, there are some downsides.
a big question mark over safety
There are risks associated with getting genes into a human body and having them carry out the desired
function. Some genes are carried in on viral vectors and these bugs have been altered so as not to infect
a patient with
a disease. However, a small number of gene therapy trials have resulted in the deaths of
Also, we simply do not know long term the potential ramifications of altering genes. For example, if
you were to stop telomeres from shortening would th
is have negative knock
on effects elsewhere in the
genome? The human genome and our whole bodies are a maze of complicated biological signals,
pathways and interrelationships. A positive change upstream could cause a negative effect
If we were all to undergo genetic modification would this limit our
? Could there be a
danger that our gene pool diminishes and that as a popul
ation we become more susceptible to being
wiped out by a hitherto unknown disease threat?
A Slippery Slope? Ethics of Human Genetic Engineering
To say that genetic engineering has attracted some controversy would be an understatement. There are
that scientists are 'playing God' and that it will lead to a two
haves and the have
nots. But is this any different to the cries of horror and fears of Frankenstein's
monster that greeted Louise Brown, the first child to be b
orn by IVF treatment? There was great uproar
in the late 1970's but IVF is now a common, if expensive, fertility treatment. And there aren't any
monsters stalking the Earth.
Having said that, genetic engineering does hold the potential that parents could (
if the technology
worked) assemble their kids genetically, to be smarter, to be more athletic or have a particular hair or
. Though it's rather fanciful to s
uggest that intelligence could be improved by the
substitution of a gene, it may be found that there are several genes that are more commonly expressed
in the genomes of intelligent people than those with more limited intellectual capacity. And parents
ht want to engineer an embryo to house a greater number of these genes. It is this genetic
engineering of humans that so frightens people, that we could somehow design the human race.
Though some people point out other potential benefits. What if it turned
out that there were sets of
genes that were commonly expressed in criminals
could we tackle crime by weeding out those genes?
The technology is nowhere near there yet, but a tiny number of parents undergoing IVF have selected
embryos to be free from genetic mutations
that have blighted generations of their family. In the
UK in January 2009 a mother gave birth to a girl whose embryo had been selected to be free
genetic form of breast cancer. Some see this as a slippery slope towards a eugenic future, others view it
as a valuable use of genetic engineering to prevent disease from striking someone down.
Society will decide how it uses this technology, and it
is for governments to weigh up the pros and
cons of genetic engineering in humans to see what may be carried out and what should be illegal. They
will be prompted by public understanding, desire and concern. It therefore behoves all of us to
at scientists are trying to accomplish and what they are not trying to do. We must all
become better informed, to equip ourselves with more information and to know the difference between
science fiction and science fact.