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Variations in the Genome

Genes and their variations (mutations) can make one person more susceptible to disease than another. But how can scientists and physicians tell if a certain variation in the sequence of DNA really plays a role in the onset of disease? The human genome and genomes of various modell organisms now allow scientists to pursue this question more systematically. Dr. Heike Zimdahl and Dr. Norbert Hübner from the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch have taken the first step towards recognizing those functionally important sequence variants. Together with the German MWG Biotech AG (Ebersberg near Munich) and scientists from the USA and Great Britain, they compared so-called complementary DNAs (cDNAs) of three different rat strains with the standard genome of the rat. As a result, they detected more than 12,000 variants. Using these results, they designed a map which, in their view, represents a valuable tool for comparative genome analysis and should help identify biomedically important genes. Their work has now been published in the renowned journal Science (Vol. 306, February 6, 2004, p.807)*.

When a gene is read, the language of the gene (DNA) is
transcribed into a different language (RNA) and subsequently translated into
amino acids, the building blocks of proteins. Proteins are gene products and
absolutely vital for building and maintaining an organism. When RNA is read
backwards, the resulting product is a DNA strand, complementary to the RNA.
These so-called cDNAs allow scientists to draw conclusions about the respective
gene sequences. Furthermore, it is possible to detect single changes in the
gene sequence, referred to as SNPs (single nucleotide polymorphisms). Applying
this technique, the scientists constructed the first cDNA based SNP map for the
rat,available to the scientific community via the ENSEMBL online database.
According to the scientists, this map is a prerequisite for systematically
screening the genome for functional variants.

*A SNP Map of the Rat GenomeGenerated
from cDNA Sequences

Heike Zimdahl1, Gerald Nyakatura2,
Petra Brandt2, Herbert Schulz1, Oliver Hummel1,3,
Berthold Fartmann2, David Brett2, Marcus Droege2,
Jan Monti1, Young-Ae Lee1, Yinyan Sun1,3,
Shaying Zhao4, Eitan Winter5, Chris Ponting5,
Yuan Chen6, Arek Kasprzyk6, Ewan Birney6,
Detlev Ganten1, Norbert Hubner1

Science, Vol. 303, 6. Februar 2004, p.807

1Max-Delbrück-Center for
Molecular Medicine (MDC), Robert-Rössle-Str. 10, 13092 Berlin-Buch, Germany

2MWG-Biotech, Anzinger Str. 7a,
85560 Ebersberg, Germany

3Max-Planck-Institute for
Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany

4The Institute for Genomic
Research, Rockville, Maryland 20850, USA

5MRC Functional Genetics Unit, University
of Oxford, South Parks Road, Oxford OX1 3QX, United Kingdom

6EMBL, European Bioinformatics
Institute, Hinxton, Cambridge CB10 1SD, United Kingdom

Barbara Bachtler
Press and Public Affairs
Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch
Robert-Rössle-Straße 10; 13125 Berlin; Germany
Phone: +49 (0) 30 94 06 - 38 96
Fax:  +49 (0) 30
94 06 - 38 33
e-mail: presse@mdc-berlin.de
http://www.mdc-berlin.de/englisch/about_the_mdc/public_relations/e_index.htm