27 - 30 May 2005

IMPRINTING AND HUMAN DISEASE Bernhard Horsthemke Institut für Humangenetik Universitätsklinikum Essen Essen Germany

Genomic imprinting is an epigenetic process by which the male and the female germ line of eutherian mammals confer a sex-specific mark (imprint) on certain chromosomal regions. As a consequence, the paternal and the maternal allele of certain genes are functionally non-equivalent. To date, approximately 80 imprinted genes have been identified. Many imprinted genes are involved in regulating resource acquisition of the embryo and fetus. In fact, it has been proposed that imprinting co-evolved with the placenta. In eutherian mammals, the fetus grows on the expense of the mother. As proposed by the genetic conflict theory (Wilkins and Haig 2003), the paternal genome is "interested" in extracting as many resources from the mother as possible. By contrast, maternally inherited genes protect the mother from being exhausted by the fetus.

Although the nature of the primary imprint is still a matter of debate, imprints are characterized by specific patterns of DNA methylation and histone modifications. Incorrect imprints can arise from errors in imprint erasure in the primordial germ cells, imprint establishment during later stages of gamete development, or imprint maintenance during postzygotic development. They can occur spontaneously without any change in the DNA sequence (primary epimutation) or as a consequence of a mutation in a cis-acting control region (secondary epimutation).

List of abstracts from the 3rd International Conference on the Female Reproductive Tract