KNOCKOUT RESTORATION. “The implantation of an SCN from wild-type mice into genetically arrhythmic Cry1/Cry2 double knockout mice restores rhythmic locomotor activity. Therefore, peripheral oscillators play only a subordinate role, if any, in establishing rest-activity cycles.” (SCN = Suprachiasmatic nucleus).
http://www.smw.ch/content/smw-2014-13984/