Acknowledgements
The authors want to thank Sylvia Finkernagel for her crucial technical contributions. The authors also wish to thank the animal research facility (TFA) of the University of Konstanz. This work was supported by a European Research Council Advanced Grant (ERC “GenAdap” 293700) to AM and grants from the Deutsche Forschungsgemeinschaft to AM and CFK (KR 4670/2-1, KR 4670/4-1), as well as a grant from the Baden-Württemberg Foundation to CFK.