It’s Gregory Brown, the brother of Dan “The Da Vinci Code” Brown.

But chances are, you won’t be hearing it at your local parish any time soon. The “sacred text” is by Charles Darwin.

The composer Gregory Brown describes himself as an introverted academic who prefers playing piano or walking his dog to standing in a spotlight. But you’ve probably heard of his older brother: Dan Brown, the author of blockbuster page-turners including, of course, “The Da Vinci Code.”
Gregory won’t be able to hide for long, though. His brother’s fact-heavy novels often send readers racing to Google, and the latest book, “Origin,” devotes an entire chapter to one of Gregory’s pieces: “Missa Charles Darwin.”
In the acknowledgments, Dan goes so far as to write that Gregory’s “inventive fusion of ancient and modern in ‘Missa Charles Darwin’ helped spark the earliest notions for this novel.”
That “fusion” refers to the form of “Missa Charles Darwin,” which follows the tradition of five-movement Latin Masses but substitutes much of the sacred text with excerpts from “On the Origin of Species” and other Darwin writings. The juxtapositions can be bracing, like “Kyrie eleison” (“Lord have mercy”) followed by the brutal line “Let the strongest live and the weakest die.”
The piece may sound like Renaissance polyphony, but its score also nods to modern science, transcribing the DNA of Darwin’s finches for the opening melody, for example, and adapting into musical variations genetic concepts like insertion, mutation and deletion.
“There’s this exploration of the edges of things,” Gregory Brown said in an interview in Boston. “Whether that edge is science and music, or religious and scientific, or sacred and secular.”
In a telephone interview, Dan Brown said that he’s “always looking for big themes,” and when he first heard the mass performed in 2011 at the Marine Biological Laboratory in Woods Hole, Mass., “it got me thinking about creationism and this sort of battle between science and religion.”
He followed the idea until it became “Origin,” a thriller — starring his signature protagonist, the Harvard “symbologist” Robert Langdon — about a brazen scientist whose discovery about the source of life on Earth and the future of humanity threatens to upend the world’s religious order.

Read on. And check out the excerpt from the mass in the YouTube video below.

You’ll never guess who composed a mass