Gameshows, Westerns and newsmagazines may come and go, but one genre that has survived over the decades: sketch comedy.


They even got the first laugh, back in TV’s earliest days when “Texaco Star Theater” was beamed across America, scattering visions of Uncle Miltie looking like scary Aunt Bertha. Today there’s “Saturday Night Live,” which sometimes even resembles its 1950s forebears, although if Berle, a little groggy near midnight, happens to catch Chris Kattan’s Mango, it’s possible he may not get the joke.


Times — and the subtext of drag acts — do change.


What doesn’t change about sketch comedy shows, though, is best described by the queen of the genre, Carol Burnett, whose self-titled variety show of the 1970s won 25 Emmys, ranking it today as the award’s fourth-biggest series champ.


‘Exposing a nerve’


“All great sketch comedy shows have one thing in common: They tap a deep pain,” Burnett says. “You’re digging down, exposing a nerve. Sometimes we’d get pretty heavy with our Momma, Eunice and Ed skits. We didn’t write jokes. The humor came out of those characters’ pain, frustration, fear and lack of self-esteem.”


Today’s TV comedy sketches are noticeably different from the older in terms of raciness. Back in the early 1960s, skits made fun of John F. Kennedy’s Boston twang. Jokes about what comes out of a president’s mouth continue to this day, but in recent years they tended to have a punchline about Monica Lewinsky and a Cuban cigar.


The newer skits have a new hostility, too, according to Entertainment Weekly TV reporter Lynette Rice: “Mean has become king in sketch comedy. ‘Saturday Night Live,’ in particular, finds much of its humor at the expense of others. We not only laugh at our former president’s peccadilloes, but take glee in the fact that he had a crooked penis. And look at what happened to Janet Reno — depicted by an extremely unattractive Will Ferrell.”


Burnett believes that modern sketch comedies lean too heavily on “easy laughs about toilet humor and sexual dysfunction.”


“They’re hurt by the writing process. There are so many writers/producers now and the corporate suits get involved. Everybody gets a vote and the shows end up getting done by committee. There’s no Sid Caesar slamming his fist down on the desk saying, ‘This is the way it’s going to be!’ “


Today’s sketch laffers can trace their ancestry to “The Red Skelton Show” and Berle’s “Texaco Star Theater,” which, in turn, grew out of vaudeville, minstrel shows, circuses, burlesques and Mississippi showboat acts. All of those entertainment formats were, in essence, the same as Skelton’s and Berle’s skeins — variety shows offering, in addition to comedy, music, magic and even juggling and acrobatics.


But it was “The Red Skelton Show” that was the first to jettison the nongags. By the 1960s, it became sketch comedy exclusively.


Snuffed out


Meantime, Burnett, Dean Martin and Sonny & Cher carried the old variety torch into the 1970s, but it soon flickered out.


“Variety shows once felt that they had to offer something for every member of the family back in the days when the average home had just one TV set,” notes “Total TV” author Alex McNeill. “By the 1970s, more sets were in the house, the family scattered to watch different things and everything changed. When ‘The Carol Burnett Show’ went off the air in 1978, it was the last of the classic, old variety shows.” On Burnett’s show, she had insisted that the performers get maximum freedom.


“We often threw the script out the window once we started a skit and then followed the wackiness wherever it took us,” she recalls. “We didn’t mind doing longform back then. Our most famous skit, the ‘Gone With the Wind’ parody, went 22 minutes. People forget that today.”


Berle notes a big change in the genre, too.


“In my day, we did everything live. It was real. It was fun. If you screwed up, too bad,” Berle says. “Now it’s all tape and retakes and canned laughter. That robs TV of its spontaneity.”


Most sketch comedy shows today are taped but “Saturday Night Live” is still just that, and even includes a music act — both aspects being a wink and a nod to its variety show ancestry.


Tom O’Neil is the author of Variety’s book “The Emmys” and is host of the awards watch Web site goldderby.com.