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Newly released details of what it means to be genetically
human will change forever the way medicine
is practiced, impact dramatically on science and industry,
and facilitate the genetic engineering of humans.
Major practical applications are expected to come
from the formulation of new drugs based on a knowledge of the chemistry
of the genes, the proteins they produce and the physiological pathways
of those proteins.
The first in-depth analysis of the human genetic code
will not only spark a staggering transformation of scientific principles,
but drastically remake the billion-dollar
gene industry that is poised to profit from the breathtaking
insights.
The existence of this human genetic blueprint will
give scientists the first opportunity to analyze the proteins that contain
the mysteries to disease and, therefore, set off a vast
and intense race to develop treatments and cures.
Academics and corporate strategists began drinking
in the implications when reports were released detailing an initial study
of the set of operating instructions for mankind, better known as the
human genome.
Sequencing, which involves determining the exact order
of DNA's four chemical bases -- commonly abbreviated A, T, C and G --
in all 3.2 billion steps of mankind's genetic "ladder" has been
accelerated by technological advances in deciphering DNA and the collaborative
nature of the effort, which has drawn upon the talents of about 1,000
scientists worldwide.
The fact that there are more proteins in the short
term gives us more headaches, but in the long term it gives us an accurate
view of the metabolic pathways that control our behavior and existence.
The most notable insight contained in the newly released
research is that the
Human genome contains
only about 30,000 genes, tens of thousands fewer than had been.
Just a year ago, scientists mostly agreed that the
number of genes in the human body was likely about 100,000. About 1,000
genes, when they exist in certain altered forms, are currently associated
with disease conditions.
At this point, researchers have elucidated the exact
chemical sequence of more than 95 percent of the genetic essence of humanity.
The discovery of the functions of new genes is also well underway.
In biology, the gene has been the currency, the elementary
particle. Now, it looks like it can't be. It's not the building block.
Simply put, there are too few genes to explain all
the complexity. What's more, the new studies show, each gene produces
about three different proteins, which actually carry out the work of the
body.
This indicates there is
something more fundamental guiding the actions of the gene.
Scientists believe these smaller units, called exons,
may be the biological equivalent of a subatomic particle, as important
to genes and cells as quarks and gluons are to atoms.
Humans use a process called "alternative
splicing" in which different parts of a protein can be
rearranged as needed -- much like parts of tinker toys -- to make different
proteins from the same basic components.
Alternative splicing is possible because human genes
are spread out over large regions of genomic DNA, and regions that code
for proteins are not necessarily continuous, allowing one gene to code
for different parts of a protein.
On the average, each human
gene probably makes three proteins, more than worms and flies do.
How the body coordinates the production of proteins
will be key tasks of scientists for the next few years.
On another level, though, the sequenced genome provides
a perspective on what makes up human life. One of the most surprising
findings to emerge is how few genes keep the human machinery running.
In fact, all humans share 99.9%
of their DNA. Dr. Francis Collins, director of the human genome
program at the National Institutes of Health, recently commented that
racial and ethnic designations "have
no scientific basis."
People of different races, he noted, can be more genetically
similar than members of the same race or ethnicity are.
It's the 0.1%
of DNA with subtle differences that make individuals unique,
including their susceptibility to disease. And it is that DNA that researchers
are focusing on to advance science's understanding and treatment of disease.
The genome project should also advance understanding
of the biological rhythms that repeat on a daily basis in humans, called
circadian rhythms. Researchers have already used computer programs to
search the entire three-billion base-pair genome and found a new gene
that has large elements identical to other genes involved with controlling
circadian rhythms.
Some scientists expect additional research to lead
to treatments for sleep disorders and jet lag.
As for the broader picture of genetic characteristics,
many scientists stress repeatedly that the one-gene one-disease model,
or one-gene one-trait, is far from what will emerge in most cases. Much
more likely is complex system of gene interaction that produces most health
problems and traits.
The
Star Ledger February
12, 2001
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