First there was bluegrass, then there was newgrass and now, perhaps inevitably, there is Jewgrass. It’s not yet a trend. Call it a development. You can find it in New York, Denver and suburban Washington, D.C. It’s still rare enough to sound like a high-concept gag — Jed Clampett in a tallis — but it’s not.

Jews have been playing bluegrass since the folk revival of the late 1950s and early ’60s made it clear it that bluegrass wasn’t just for hillbillies anymore. That revival transformed a rather small niche within commercial country music into what looked like a modern — and authentic — folk music, open to city kids who disliked the shiny surfaces of late-’50s pop. Because of this, there have been genuine Jewish bluegrass heroes, like David Grisman and Andy Statman. But Jews playing bluegrass are not necessarily Jews playing Jewgrass. This type of music requires real Jewish content, whether it’s lyrics or music or both. You could say that Jewgrass is American-roots music with an Old World accent, or Jewish roots with a down-home twang.

Oddly enough, bluegrass is well suited for this kind of ethnic makeover. For all its Appalachian origins, bluegrass is, like most forms of music, a hybrid. Its musical structures can be a little rigid, but you can hang a lot of stuff on them. To be sure, bluegrass came from the hill country of the South, but people who listened to the radio invented it. They were virtuosos who played swing jazz on the mandolin. They knew what blues sounded like. They just never had heard of klezmer.

As the name indicates, the group Margot Leverett and the Klezmer Mountain Boys is trying to remedy that. The most prominent Jewgrass band at the moment, the musicians blend classic bluegrass with what could be called classic klezmer by whipsawing from one to the other within a single song. The configuration of its instruments is more klezmer than bluegrass. Leverett, who was one of the original Klezmatics, is a classically trained clarinetist. She claims that for years, bluegrass musicians were leery of her, precisely because the clarinet is unimaginable in bluegrass. (What’s more, her band doesn’t have a banjo.) Nevertheless, because she keeps good company now (her fiddler and her mandolin player are famous in bluegrass circles), she has begun to gain acceptance — and not just in New York, where she lives. The Klezmer Mountain Boys play gigs around the country and even received a standing ovation in Kentucky, the mothership of bluegrass.

According to Leverett, the musical marriage between the Appalachians and the Carpathians is a natural. Beyond the similarities between the peoples themselves (both poor, nostalgic for home and quite religious), “klezmer and bluegrass come from the same place in the human heart,” she said. They’re both soul music for the dispossessed.

While the mountain folk of the South and the Jews from the Pale might have been religious, Margot Leverett and the Klezmer Mountain Boys do not play religious tunes. Bulgars, medleys of songs by Bill Monroe and lullabies, maybe, but not sacred melodies from either tradition. This isn’t true of other Jewgrass bands. Shalom Feivel and Rocky Mountain Jewgrass plays overtly religious music, although of different kinds, as do the Sinai Mountain Boys.