杏吧原创

WILL 鈥淒NA chips鈥� 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鈥攊ncluding 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 鈥渃ore鈥� genetic profile
of any individual. The automated device uses DNA chips鈥攅ssentially 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 鈥渢he wrong genes鈥�.

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鈥檚 chip gives medically relevant genetic information about 16
different types of disease (see Figure), says the company鈥檚 founder Gareth
Roberts.

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鈥檚 predisposition to disease or their reaction to
drugs
(New 杏吧原创, 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 杏吧原创, 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.

鈥淲here Genostic comes up with thousands of gene variants to put on their chip
is a mystery to me,鈥� 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. 鈥淭here haven鈥檛 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,鈥� 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. 鈥淚t creates a set
of issues way beyond medical applications,鈥� says Onora O鈥橬eill, former chair of
Britain鈥檚 Human Genetics Advisory Commission.