DKIM can be turn off / on on per list basis. This section describe how a list can be configured in order to apply DKIM signature to outgoing messages (messages distributed to subscribers). You should check the DKIM chapter of this documentation. By default those parameters can't be edited by anyone else then the listmaster.
The following parameter can be set at the list level. In almost all cases you will never need to do it list by list. Instead you can use default by setting those parameters in robot.conf file.
List of parameters