It was only one year as the show was a fringe show in the ratings and the Network would only renew if noone asked for a raise.
Roger C Carmel refused and they had to recast in a hurry with Richard Deacon, the least Bohemian Actor they could have chosen.
Lets say Dharma and Greg was inspired by the Mothers In Law.
More than the Mothers In Law was by Abies Irish Rose which was based on religous differences.