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Epigenetics
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In the past few years, the DNA sequence of various
species including yeast, plants, worm, fly, mouse and
man has been determined. In an ongoing effort, an inventory
of variations in the human and mouse DNA sequences is
being made. These variations account for most of the
heritable diversity of a species, which is the subject
of genetics.
Although most cells of an organism contain the same
DNA sequence, not all of the genes are used in every
cell at every time. At various stages during development,
dramatic changes in the pattern of gene expression occur,
which then are stably inherited through several cell
divisions. This variation of gene expression is the
subject of epigenetics, a term which was introduced
in 1953 by Conrad Waddington. As these patterns are
potentially reversible, they can not be explained by
DNA sequence variation. Thus, there must be a code above
the DNA sequence level that specifies the selective
use of genetic information during development. The epigenetic
code is based on the modification of DNA and chromatin,
for example by methylation.
Both the DNA sequence and the methylation pattern
of a gene can be affected by a mutation. An inappropriate
change of the methylation pattern is called an epimutation.
In fact, it has been estimated that epimutations occur
much more frequently than DNA sequence mutations. Epimutations
contribute to many diseases including cancer and mental
retardation. There is also growing concern that exogenous
effects such as nutrition and assisted reproduction
may increase the rate of epimutations.
Epigenetics is a rapidly growing field. At the ESHG
meeting, one symposium (S3, Sunday 17:00) and
the ESHG award lecture
(by Prof. Bernhard Horsthemke, Essen, Tuesday 13:45)
deal with epigenetics.
Dr. Bernhard Horsthemke, Univ.
Essen
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Pressekontakt
Dr. rer. biol. hum. Christine Scholz
Deutsche Gesellschaft für Humangenetik e.V.
Inselkammerstr. 5
82008 München-
Unterhaching
Tel. (0)89/61 45 69 59
Fax (0)89/55 02 78 56
Email presse@gfhev.de
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