|SHIRLEY RENFREW PARTRIDGE|
"THE PARTRIDGE FAMILY"
It can't be any closer a relationship than cousin, because Shirley Renfrew grew up in Southern California, while Dr. Renfrew had a Southern accent. (I'm thinking Louisiana, perhaps the Delta region.)
They also don't look anything alike, but that's not a problem when it comes to cousins. Hey, they're not all "identical cousins" in Toobworld.....