All department heads and boards and commissions shall be appointed with reference to their qualifications and fitness, and for the good of the public service, and without any regard whatever to their religious faith or party affiliations. The spouse, spousal equivalent, child, parent, grandchild, grandparent, brother, sister, half-brother, half-sister, or the spousal equivalent of any of them, whether by marriage, or by blood, or by adoption of the mayor or any councilperson, shall be disqualified for appointment to a board or commission during the term for which the mayor or councilperson is elected.