By Maggie Fox, Health and Science Correspondent
WASHINGTON
(Reuters) - Our future may not lie in our genes, after all.
Two separate
teams of researchers will report on Monday that they have taken
the first in-depth look at the human genetic code and found about
half what they expected to find. Instead of 60,000 to 80,000 genes,
we have only 30,000 to 40,000.
Both teams
agree this means that, in humans anyway, it is proteins that matter
-- much more so than genes.
``Those who
are looking for forgiveness of responsibility for their own lives
in the genetic code will be very disappointed,'' Craig Venter,
president and chief scientific officer of Celera Genomics (news
- web sites) Inc., the private company that did one of the studies,
said in a telephone interview.
The human
body, it seems, is set up to adapt to its environment, by cutting
up and recombining the protein ''products'' of genes to make a
protein suitable for the circumstance.
Each gene
makes one protein -- this is the basic function of any cell. Researchers
had known that proteins often have to be sliced in a certain way,
a process known as cleaving, before they do anything useful.
``Most of
biology happens at the protein level, not the DNA level,'' Venter
said.
What had not
been known was the degree to which this is true. The implications
could be profound for medical science, which had hoped to find
easy genetic answers to disease and to how people will respond
to drugs.
Gene Patents
``Irrelevant''
``This shows
how irrelevant human gene patents are,'' Venter said. ``The drug
industry has been saying 'one gene, one patent, one drug'. But
the uses for this approach can be counted on fingers.''
Both teams,
who publish their findings in the rival scientific journals Nature
and Science, are fairly certain.
``Given all
the tools that we threw at this problem, we cannot imagine that
there are many more genes,'' Mark Adams, vice president at Celera,
told a briefing for journalists.
``We only
have twice as many genes as a fruit fly. But we are more complex.
We can think more thoughts. Our bodies can do more things.''
Humans have
3.1 billion base pairs of genetic code. A base pair is a joining
of two nucleotides -- known by the letters A,C,T and G. These
repeat over and over in various combinations to make amino acids,
which in turn combine to make proteins.
``The size
of the genome, the number of base pairs, is irrelevant to biology,''
Venter said.
``Corn has
the same number of genes as humans. The lily plant has 91 billion
pairs of genetic code.''
Each protein
equals a gene, but there are long stretches of base pairs that
do not code for proteins, areas once known as junk DNA. These
areas may help control genes.
Only just
over one percent of the genome is accounted for by protein-expressing
genes. Venter says all this means genes, per se, are just a small
part of the story.
``Genes don't
determine whether you get colon cancer,'' he said. ``They determine
whether you have an increased risk for colon cancer. We get a
set of probabilities from our genetic code, a sort of range of
parameters that we can work within.''
Kind Of Humbling
``It's kind
of humbling, isn't it?'' Ari Patrinos of the U.S. Department of
Energy (news - web sites), which funded much of the public effort,
said in a telephone interview.
``There are
very, very few traits or diseases that are monogenic (caused by
a single gene). It's been an emerging consciousness over the past
five years, and the recognition that ... our genes don't control
everything.''
It also means
the so-called ``junk DNA'' may be more important than at first
thought.
``We just
don't know. We don't call it junk,'' Venter said.
Eric Lander,
who heads the genome lab at Massachusetts Institute of Technology
(news - web sites)'s Whitehead Institute, said the ''alleged junk''
provides a history.
``The junk
is amazing. Every piece of junk in the genome represents a transposable
element,'' he said.
In other words,
it is genetic material that people got from elsewhere, such as
from bacteria the readily lend their DNA out, retroviruses that
inject their genetic information into cells, or by a cut-and-paste
process done by genetic elements known as transposons. If it stayed
there through generations, it might do something useful.
Lander thinks
some of the ``junk'' may help regulate genes -- a role that is
more important the fewer genes there are.
And some of
the genes are borrowed, too. Lander said his team found that the
gene for monoamine oxidase, an enzyme implicated in depression
and targeted by drugs called MAO inhibitors, came from bacteria.
Not Everyone
Agrees
Not everyone
agrees with all the conclusions.
``We know
that they have missed very, very many genes that we know exist,''
William Haseltine, head of Rockville, Maryland-based Human Genome
Sciences Inc., said in a telephone interview.
``They have
missed at least half the genes, maybe more,'' added Haseltine,
whose company holds more than 100 gene patents. ``They have no
medical discovery and they only found a third of the genes. That's
a bore.''
Haseltine,
whose company looks for ``expressed'' genes -- those that actually
make a protein -- by using bits of DNA called expressed sequence
tags (ESTs), says he believes there are 120,000 human genes.
Another company
that says it has explored the genome, Palo Alto, California-based
Incyte Pharmaceuticals Inc., maintains there are 140,000.
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