By Jean Lowerison

Everybody knows about rock ‘n’ roll greats Elvis, Little Richard, Chuck Berry and Jerry Lee Lewis. But not many know about the influence of Sister Rosetta Tharpe and Marie Knight on that music form.

Rock ‘n’ roll came out of the gospel and soul traditions represented by the likes of Mahalia Jackson. But the lesser-known Sister Rosetta Tharpe took gospel to a different place when she started “swinging” it in a way that made it welcome in clubs as well as churches. She was a huge draw in the 1940s, and her stylistic innovations led to her being named the “godmother of rock ‘n’ roll.”

George Brant’s musical profile “Marie and Rosetta” — playing at Cygnet Theatre — begins in a funeral home in Mississippi, with two caskets and a piano onstage. It opens with 30-something Rosetta (“Sister” was a nickname, not a job title; she was no nun) auditioning starstruck 20-something Marie Knight as a performing partner.

Rosetta’s gospel stardom was beginning to wane and she was looking for something new to offer. She had heard Marie as part of Mahalia Jackson’s backup quartet. Marie had a “churchier” sound and fine piano technique, but a reluctance to let go and wail in the way that made Rosetta famous.

Why are they in a funeral home? And why does Rosetta say they will sleep there tonight? Because these women are African-American, and there is nowhere else in pre-Civil Rights Act Mississippi they could spend the night. Marie is downright creeped out by the suggestion but impressed enough to have been chosen by Rosetta to stick around.

Brant doesn’t give much information, or even much of a coherent story about these women. Most of what passes for dramatic action centers on Rosetta’s efforts to get Marie to loosen up and let the music swing. Though occasional lines like Rosetta’s “Your piano’s an old maid with a gray tabby on her lap” are amusing, that’s not much of a plotline.

Director Rob Lutfy understands this and plays down the bland paint-by-numbers script, allowing the audience to take this as what it really is — a concert.

Soprano Noël Simoné Sippler plays Rosetta with assurance, though she would be easier to understand if she spoke slower. But she sings with plenty of power and heart, and also plays a mean piano and guitar. She’s a good foil for Amaiya Holley’s Marie, an alto powerhouse who can also tickle those ivories and play a guitar with authority.

Together, they really do swing. Listen to these ladies and see if you can spot the elements of rock ‘n’ roll in their sounds.

—Jean Lowerison is a long-standing member of the San Diego Theatre Critics Circle and can be reached at [email protected].