If things had turned out differently, Mollie O'Brien might have been a Broadway star instead of singing bluegrass, blues and folk music in a trio with her husband, Rich Moore, and bassist Eric Thorin, who the West Virginian tours Scotland with this coming week.

"I was attracted to the bright lights of New York and I was really into theatre and musical theatre," says O'Brien down the line from her home in America's mountain time zone. "But maybe through being a small-town girl or maybe through just feeling over-awed by the whole thing, I felt like a tiny fish in a giant pool, wound up taking a job in the Garment District and after four years I decided to get out and get back to things that were familiar to me."

She made the right move because back home in Wheeling, West Virginia, she began to find her own voice through singing in bars and when she followed her younger brother Tim, whose group the Ophelia Swing Band used to sleep on Mollie's floor when they passed through New York, to Colorado, she met and married Moore, earned a living as a blues and rhythm and blues singer and eventually hooked up again with Tim.

By this time, Tim's new band, the bluegrass styled Hot Rise, was making big waves on the American roots music scene. Then, in 1988, he and Mollie recorded the album Take Me Back and although they don't perform so often these days due to their busy individual schedules, they quickly became established as one of Americana's top brother and sister acts.

"Tim and I were always close because we were the tail end of five siblings," she says. "The youngest of the other three was six years older than me and in those days when the baby boomers were finding their own way, this amounted to a different generation. Our mother would take Tim and me to see concerts – Count Basie, Dave Brubeck, Ray Charles, symphony orchestras, the Fifth Dimension, all these people toured to even a small place like Wheeling – and when we started singing, we sang together in the local Catholic Church choir at a time when folk groups were starting to be incorporated into mass and did some coffee shop gigs in a kind of Peter, Paul & Mary style."

The O'Briens' links to Ireland – Tim and Mollie's immigrant great-grandfather walked all the way from Maryland to settle down in Wheeling – didn't impact on their music until later but Mollie remembers a great aunt who could play any song she heard on piano and those genes may account for Tim and Mollie's aptitude for music. That and listening to the wide range of music available on the radio, although the local pop station closed down at dusk in the 1960s, she recalls.

"I always liked a lot of different styles of music," she says. "I mentioned Ray Charles earlier and he used to come to Wheeling every year, so he was a big influence. But I also listened to a range of singers including Joni Mitchell, Bonnie Raitt, Dinah Washington and Frank Sinatra, loved the blues of Memphis Minnie and Willie Dixon, and liked songwriters such as Randy Newman, John Hiatt and Steve Goodman.

"So all of that fed into what I do, along with show tunes, and it's possible to encompass all of that in a set if you present it in the right way. You have to show the audience you relate to what you're singing and that way you can take them with you, whatever direction you choose to take off in."

It helps that, in Moore, O'Brien has, for her, the perfect accompanist, a guitarist who having worked and lived with her for 30 years can read her intentions as a singer as she moves from genre to genre. Having Thorin along adds a very able bass player and an arranger whose sure and imaginative production on their latest album, Saints and Sinners, was responsible for the unusual but highly effective pairing of pedal steel guitar and oboes.

"Eric's a great singer, too, so we have three voices as well as guitar and bass, and it works really well," says O'Brien. "I haven't been in Scotland as much as Tim has but I really enjoyed playing Celtic Connections the year before last and I'm hoping this trip will lead to us getting over more regularly."

Mollie O'Brien, Rich Moore and Eric Thorin play Heart of Hawick on Friday; The CatStrand, New Galloway, Saturday; Biggar Corn Exchange, Sunday; Old Library, Kilbarchan, March 25; Leith Folk Club, March 26; and Acoustic Music Club, Kirkcaldy, March 28.