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What to expect in molecular medicine?
The first phase of the ambitious
international effort to determine the entire sequence of the human
chromosome set is virtually complete. Human Genome Project scientists plan
to finish the human sequence by 2003, along with a database of the most
common sequence variations that distinguish one person from another. This
knowledge base, freely available to any interested person over the Internet,
will revolutionize biology and medicine. But how? What will be different 20
years from now because the human genome was sequenced?
Only time will prove
the accuracy of the following predictions, but here is a list of some
effects we might expect in 2020.
More Effective
Pharmaceuticals
A virtually complete
list of human gene products will give us a vast repertoire of potential new
drugs. From 500 or so drugs in 2000, at least six times this number will
have been identified, tested, and commercialized in 2020. All will be
manufactured by recombinant DNA technology so they will be "reagent-grade
pure," just as human insulin and growth hormone are today.
Your medical record
will include your complete genome as well as a catalogue of single base-pair
variations that can be used to accurately predict your responses to certain
drugs and environmental substances. This will permit you to be treated as a
biochemical and genetic individual, thus making medical interventions more
specific, precise, and successful. In addition, the increased power of
medicine to predict susceptibility to specific diseases will allow you to
alter your lifestyle to reduce the likelihood of developing such diseases or
to be treated with preventive or disease-delaying medicine.
Treatment failures
occasionally happen today with drugs for hepatitis C infections,
antihypertensive, and certain anti-depressants (selective serotonin reuptake
inhibitors like Prozac). In the next 15 to 20 years, more effective drugs
will be developed, and doctors will test individual genetic profiles against
panels of drugs available for a specific condition and choose the treatment
with the greatest potential benefit.
Today, some 100,000
people die each year from adverse reactions to drugs, and millions of others
must bear uncomfortable or even dangerous side effects. We see such current
examples as heart-valve abnormalities from diet drugs, muscle damage from
some hormone-regulating drugs, and nervous system effects with certain types
of anti-depressant medications. As genes and other DNA sequences that
influence drug response are identified, we can expect the number of toxic
responses to drop dramatically and most side effects to be eliminated.
Societal
Implications
Another consequence of
greater knowledge about individual variation is more disturbing, and we may
face some unpleasant consequences unless society makes some hard choices.
These considerations include the likelihood that your medical information
will be available to others not in the medical profession--your insurer or
employer, perhaps. Employers may have a strong motive to learn about your
risks of developing certain conditions and to.
Genetic
Testing, Therapy
Although now plagued by
technical difficulties, gene therapy for single-gene diseases will be
routine and successful in 20 years. Certain aberrant disease-associated
genes will be replaced with normally functioning versions, and several
hundred diseases will be curable. Neonatal genetic testing for these
treatable conditions will be routine.
Some of the mysteries
of early embryonic development will be solved. We should know the timing of
expression of most, perhaps all, of the human gene set. We may have learned
how to direct differentiation so that a desired cell type or even relatively
"simple" organs and parts of more complex organs can be grown for
transplantation. In 2020, we will have made substantial progress towards
true "cloning" of certain organs, but many difficult technical steps will
remain before successful cloning of a heart or liver.
As genetic testing
using DNA sequence becomes more common, less expensive, and more accurate,
it will be used commonly and reliably in cases of mistaken identity, false
or misattributed paternity, and the identification of missing persons.
Misguided attempts to ascribe behavioral tendencies to a person's genes will
cause many problems, not least for the courts that must resolve disputes
when an individual's behavior and actions conflict with laws. Should society
(via the courts) interpret behavior as a consequence of free will or as
influenced by genetic constitution? At what point does society mitigate
responsibility or punishment?
Understanding
Life
On the brighter side,
an inevitable consequence of the genome project will be a much greater
understanding of fundamental biology. Already, some three dozen organisms
(mostly one-celled microbes) have been completely sequenced. The fruit fly,
the latest organism to be sequenced, is being used to model the essential
features of human disorders such as Parkinson's, making possible a powerful
genetic approach to garnering knowledge about diseases as well as to
developing more effective treatments. In 2020, perhaps 1000 complete genomes
will be in hand. Besides furnishing insights into evolution, this vast
repertoire of new genes and their products can be explored for their
potential in solving challenging problems such as environmental cleanup.
We will fitfully and
slowly gain some insights into biological complexity. In 2020, we will know
how to build a functioning cell capable of free-living existence. We will
understand certain pathways used by this simplest cell, but there still will
be unanswered questions about it. We will be virtually no closer than we are
today to the mysteries of such true "emergent" properties as intelligence in
complex multi cellular organisms.
Challenges
So the Human Genome
Project will have vast and largely positive impacts on people living in
2020. Of the various predictions noted above, the last two are the most
profound because the most powerful and momentous impacts come from
fundamental knowledge, usually in unforeseen ways. As this astonishing
treasure trove is introduced into society, we need to be alert to challenges
and misuses of the knowledge about ourselves. Society as a whole, not just
genome scientists, must address these considerations. It has to be all of
us.
By
: Krishna Pudasaini
5/111 Hampden Road Artarmon
NSW 2064 Sydney Australia.
Bachelor’s in genetic engineering (Australian national university)
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