Scientists map key chromosome Sequence identifies genes
linked to deafness and cancers
LONDON - Scientists announced Wednesday they have finished
sequencing human chromosome 7, which contains genes linked
to hand and facial development, cystic fibrosis, deafness,
lymphoma and other cancers.
It is the sixth and largest chromosome to be sequenced so
far and contains 153 million letters of DNA and about 1,150
genes, including one which may help to explain why cancer
cells are resistant to some drugs, and others that are
involved in the body's immune response.
"This is another volume in the encyclopedia that is
research ready. There are a number of genes that are
involved in human cancers that are going to give us a good
understanding of what goes on in the genomes of people that
have these types of cancer," said Dr. Richard Wilson, the
director of Washington University's Genome Sequencing
Center in St Louis.
"It gives us a leg up on designing new therapeutics that
will help us treat them," he added.
Scientists from several centers in the United States and
Germany completed the sequence which is reported in the
latest edition of the science journal Nature.
In addition to the gene for cystic fibrosis, chromosome 7
also contains several genes for Williams-Beuren syndrome, a
rare disorder that causes unusual facial appearance and mild
mental retardation.
"I think it will help us understand some of the genetic
components of head and face development. There are a number
of genes for that. There are also a number of genes involved
in various types of white blood cell cancers, lymphoma and
leukemia," Wilson added.
The finished sequence, which is freely available on the
Internet, provides a treasure chest of information for
scientists studying those diseases.
It will allow scientists to look at people who have these
diseases to understand the underlying genetics and to
develop treatments such as the leukemia drug Glivec, which
are aimed at gene products.
"If we can correlate other genes on chromosome 7 with some
of these lymphomas and leukemias it may be possible to
design drugs that go right after those types of (gene)
products," Wilson added.
Each chromosome is made up of a molecule of DNA in the shape
of a double helix which is composed of four chemical bases
represented by the letters A (adenine), T (thymine), G
(guanine) and C (cytosine). The arrangement, or sequence, of
the letters determines the cell's genetic code.
Copyright 2004 Reuters Limited.
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