Nowhere to hide
A gene profiling system threatens to reveal
your innermost secrets
WILL "DNA chips" that reveal your genetic makeup within
minutes prove to be awesome medical tools or the means of
genetic discrimination? We could find out sooner than
anyone expected. A British biotech start-up has filed for a
patent on a device that can detect variants of over 2500
genes--including genes that affect behaviour and intelligence.
Researchers with the company Genostic Pharma of
Cambridge have worked out the blueprint for a system which,
they believe, can provide a "core" genetic profile of any
individual. The automated device uses DNA
chips--essentially sensors that can detect many thousands of
gene fragments at once. The company expects to start
making prototype chips within months.
It says that the device will help doctors to find out if people
are predisposed to particular diseases and tailoring
treatments to individuals. But such devices could also be
used by unscrupulous employers or insurance companies to
reject applicants with "the wrong genes".
Rival DNA chip systems tend to focus on gene variations
relevant to just one disease, such as breast cancer, or to a
potential adverse drug reaction. But Genostic Pharma's chip
gives medically relevant genetic information about 16
different types of disease (see Figure), says the company's
founder Gareth Roberts.
[log in to unmask]" ALT="Chart: Your health on a chip - medical area vs. number of genes and variants" BORDER=0 height=364 width=302>
Roberts and his colleagues at Genostic Pharma combed the
scientific literature for common gene mutations called
single-nucleotide polymorphisms, or SNPs, which can alter
people's predisposition to disease or their reaction to drugs
(New Scientist, 14 November 1998, p 32). They then plucked
the entire sequences for these genes out of publicly available
sequence databases. In a 700-page patent application,
Roberts lists all the chosen genes plus known variants.
To create its genetic profiling system, Genostic Pharma must
take short stretches of DNA from each variant of each gene
and fix them to a specific spot on the surface of the DNA
chip. To test a blood or saliva sample, researchers will break
down its DNA into fragments, attach fluorescent markers and
wash them over the chip. The fixed DNA strands will grab any
matching gene fragments that pass by. The fluorescent tags
will then reveal by their position the identity of each gene
captured from the sample (New Scientist, 14 November
1998, p 46).
The genes Roberts has chosen to include on the profiling
chip are the ones he thinks are relevant to a range of
conditions, from cancer and heart disease to headaches and
impotence. But others doubt enough is yet known about the
human genome for Roberts to make these choices.
"Where Genostic comes up with thousands of gene variants
to put on their chip is a mystery to me," says Francis Collins,
director of the US National Human Genome Research
Institute near Washington DC. Daniel Cohen, chief genomics
officer at Genset of Paris, agrees. "There haven't been
enough population studies, as far as I know, to assess with
enough precision the risk or predisposition for any of the
diseases mentioned in the patent," he says.
Others are not convinced that the chip is intended for entirely
therapeutic purposes. The patent lists 500 variants of genes
related to psychoses and personality, for example, as well as
250 linked to behaviour. "It creates a set of issues way
beyond medical applications," says Onora O'Neill, former
chair of Britain's Human Genetics Advisory Commission.
More at: www.derwent.com/resource/interest.html
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