Scientists map chromosome 14, site of more than 60 human diseases

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Scientists map chromosome 14, site of more than 60 human diseases --- French

and American scientists have mapped chromosome 14, the longest sequenced to

date and the site of more than 60 disease genes, including one linked to early

onset Alzheimer's. The feat enlisting nearly 100 researchers marks the fourth

of the 24 human chromosomes mapped so far as part of an international effort.

Scientists at Genoscope, the French national sequencing center, said the

chromosome is comprised of more than 87 million pairs of DNA, all of which have

been sequenced so that the chromosome's map includes no gaps. " At the present

time, this is the longest piece of contiguous DNA that has been sequenced. We

made an effort to close all the gaps, " said Genoscope's director, Jean

Weissenbach. The researchers describe chromosome 14 and its 87,410,661 pairs of

DNA -- a fraction of the total 3 billion pairs found in human genome -- in a

paper to be published online Thursday by the journal Nature. The project was

led by Genoscope, with contributions from scientists at Seattle's Institute for

Systems Biology and the Washington University School of Medicine in St. Louis.

The scientists identified 1,050 genes and gene fragments, among them more than

60 disease genes. Those include genes linked to early onset Alzheimer's,

spastic paraplegia, NiemannPick disease and a severe form of Usher syndrome.

Although the accomplishment is noteworthy, it does not mean science is any

closer to conquering Alzheimer's, said Bill Thies, vice president for medical

and scientific affairs for the Alzheimer's Association in Chicago. He said the

chromosome 14 gene linked to early onset Alzheimer's accounts for only a

fraction of cases of the degenerative brain disease. Several genes, as well as

environmental factors, are known to play a role in a person's risk of

developing Alzheimer's, Thies said. During the last three years, nearly

complete sequences of chromosomes 22, 21, 20 -- and now chromosome 14 -- have

been published. By April, researchers around the globe hope to complete the

sequencing of the remaining 20 chromosomes, said Mark Guyer, director of the

division of extramural research at the National Human Genome Research

Institute. April is also the 50th anniversary of the publication of D.

and Francis H.C. Crick's 1953 paper in Nature describing DNA's double-

helix structure. Guyer said the institute, one of the National Institutes of

Health, intends to mark the occasions by publishing a paper outlining its

vision of the future human genetics studies. " Once we've sequenced the

chromosomes, that is essentially just the basic set of instructions. We still

need to learn how to read the instructions and understand what they mean, " he

said. --- On the Net : Nature : http://www.nature.com : Genoscope :

http://www.genoscope.cns.fr/externe : National Human Genome Research

Institute : http://www.genome.gov/ --- Copyright 2002 IndyStar.com. All rights

reserved - http://www.indystar.com/data/wire/out/0101ap_n002aaa109.html - By

Rick Callahan Associated Press - Last updated 02:04 AM, EST, Wednesday, January

01, 2003 - Hold For release until 2 p.m. EST