Would Mike Minor have gotten a role on Petticoat Junction in not for the fact that he was related to Don Fedderson?
Would Barry Van Dyke have gotten a role on Diagnosis Murder if not for the fact that he was Dick Van Dyke's son?
Are there other cases of nepotism within the sitcom community?

Petticoat Junction also has Linda Kay Henning, Paul's daughter.

You have Gary Valentine, Kevin James brother, playing his cousin on King of Queens. Young Marlo Thomas was placed in The Joey Bishop Show, produced by her dad. I'd say they were both fine in their roles.

Garry Marshall casting her sister Penny in The Odd Couple and Laverne and Shirley.

Would Mike Minor have gotten a role on Petticoat Junction in not for the fact that he was related to Don Fedderson?
Would Barry Van Dyke have gotten a role on Diagnosis Murder if not for the fact that he was Dick Van Dyke's son?
Are there other cases of nepotism within the sitcom community?

I thought Barry Van Dyke was OK, he did get other parts outside of Dick Van Dyke related projects. That said, his career is very much Dick Van Dyke centric.

Mike Minor is another story altogether. He was one of the worst actors I have ever seen on nighttime network television. He was in way over his head on Petticoat Junction, he turned in reliably wooden performances in every episode he was in. After the series ended Paul Henning used him in a few episodes of the Beverly Hillbillies, there was one scene I'll never forget. He plays an out of work actor owing back rent, his landlord, played by the great Charles Lane, wants to know when he's getting his rent money, Minor's line is, I'm expecting a check from MGM any day, Lane lights up, MGM! Minor replies, yeah, my grandmother. I think it was a pretty funny line and Lane sets him up beautifully, but Minor's wooden delivery spoils it. If you look at his IMD credits after Petticoat ended they are mostly soap operas and smallish one-offs. Of the few that he has, most are associated with either a project his father worked on or someone associated with his father worked on. For example, he appears in an episode of CHIPS, the director was Don Weis who had worked for Fedderson on the old Fess Parker Show.

Don Fedderson's other son, Gregg, had a recurring role on Fedderson's series Family Affair, as Cissy Davis' boyfriend. I think the characters would have married if the series lasted another season.

Here's one I think is quite obvious. I forget which of her sitcoms it is, but after I Love Lucy, it was either on The Lucy Show or Here's Lucy, Lucille Ball's real life son and daughter Desi Arnaz, Jr. and Luci Arnaz played her son and daughter in one of them.

Ed.

On NCIS, Sean Murray, who plays McGee, is the stepson of the show's producer, Donald Bellisario.