1. Max Planck Institute of Biochemistry, Martinsried, Germany.
2. Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.
3. Boehringer Ingelheim Pharma GmbH & Co KG, 88397 Biberach, Germany.
4. Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria.