Tonight’s two debuts of new series offer two prototypes of TV genres.

The first, “Back to You,” airing at 8 p.m. on Fox, is proof that the network sitcom needn’t be declared dead.

“Back to You” stars sitcom veterans Kelsey Grammer (“Frasier”) and Patricia Heaton (“Everybody Loves Raymond”) as an uneasy pair of news anchors in Pittsburgh. The two have a history, and after Chuck Darling (Grammer) gets fired at a job in Los Angeles, he comes crawling back to Pittsburgh and Kelly Carr (Heaton), who isn’t welcoming him back after 10 years as the lead anchor.

Grammer and Heaton are ably supported by Fred Willard as an old-school sportscaster, Ayda Field as the Latina weathergirl and Ty Burrell as the field reporter who lusts after the anchor chair.

Directed by sitcom veteran James Burrows, “Back to You” isn’t instantly a newsroom classic such as “The Mary Tyler Moore Show” or “Murphy Brown.” But it is definitely a reliable new comedic vehicle for Grammer and Heaton, and could grab older viewers away from its time-slot competition.

The other newcomer falls in the teen-angst drama category, recently vacated by “The O.C.” Not surprisingly, “Gossip Girl,” airing at 9 p.m. on the CW, is the baby of “O.C.” creator Josh Schwartz.

Based on a series of young-adult novels by Cecily von Ziegesar, “Gossip Girl” focuses on privileged prep school teens on Manhattan’s Upper East Side and the anonymous blogger Gossip Girl (voiced by Kristen Bell), who provides gossip about this exclusive circle.

The opener looks at the rift that’s formed between former BFFs Serena (Blake Lively) and Blair (Leighton Meester). Serena has just returned from boarding school (why she went is a mystery) and Blair has taken over her spot at the top of the social ladder and doesn’t want to give it up. Also, Blair’s longtime boyfriend, Nate (Chace Crawford), has secret feelings for Serena. (Yes, many of its young actors obviously attended the School of Longing Glances.)

There are other pretty young things and their attractive parents, but frankly it’s hard to tell them apart. They’re more stereotypes than characters: the bitchy one, the predatory one, the nice one, the nice one’s naive younger sister, etc.

“The O.C” had this same problem at first, but developed nicely. With sexy lead-in “America’s Next Top Model,” “Gossip Girl” should get the chance to evolve as well, with nothing else in that time slot geared toward the young audience it wants to attract.