Migratory Mutation

A 'cancer gene' is at the heart of this tale of history, family and heartbreak

In February 1997, Shonnie Medina, a vivacious 26-year-old woman living in the San Luis Valley of southern Colorado, discovered a lump in her breast. The lump was found to be cancerous, and her doctor recommended a mastectomy.

Shonnie, however, declined surgery and instead sought alternative therapies, including a series of unorthodox treatments at a clinic in Tijuana. Unfortunately, these efforts failed, and she died in January 1999.

While it's unusual for a woman so young to develop breast cancer, Shonnie had the genetic deck stacked against her. Shortly before her death, testing revealed that she possessed a genetic mutation (one that was later discovered to be rampant on her father's cancer-riddled side of the family) which made her highly prone to breast cancer. It is a mutation that is found almost exclusively in people of Jewish descent.

A new book, The Wandering Gene and the Indian Princess: Race, Religion, and DNA, by Jeff Wheelwright, Life magazine's longtime science editor, tells the compelling story of Medina and the genetic aberration that led to her demise. Tracing the path of that mutation from its inception in a Jewish progenitor around the time of the Babylonian captivity to its eventual arrival approximately 2,500 years later in the American Southwest, Wheelwright places the poignant story of a family's love and suffering within a framework of history, religious and ethnic identity, and the vagaries of genetic evolution.

The gene afflicting the Medina clan was discovered by genetic researchers in the mid-1990s. The "most studied, most worried-over piece of DNA in the world," it is often referred to as a breast-cancer gene, but it's actually a tumor-suppressing gene that, when flawed, loses the ability to keep cancerous cells in check.

Geneticists know that the mutation appeared as long ago as the Babylonian exile, because it is found among the descendants of the many isolated colonies of Jews that formed throughout the Near East after the Jewish exodus from Babylon. Following the fall of Jerusalem in 70 A.D., Jews migrated westward into central Europe and the Iberian Peninsula. It's probable that the gene made its way to the New World during the Spanish conquest, carried by conversos, Sephardic Jews who had been coerced into converting to Christianity by the Inquisition.

Among the conversos were those who continued to practice the rituals and traditions of Judaism in secret, passing them on to their children. As a result, numerous Hispanic families in the Americas (including members of Shonnie Medina's extended family) still observe—in many cases, oblivious to their Judaic heritage—Jewish customs that have filtered down through the generations. In a fascinating chapter, Wheelwright describes the radical shift of identity often experienced by Hispanic crypto-Jews when they discover their Jewish roots.

Identity development and its effect on attitude and behavior is a core theme, especially as it pertains to the story's central mystery: Shonnie's decision to forgo conventional medical treatment. Elaborating on the intricate mix of religion and ethnicity in the San Luis Valley, Wheelwright suggests that Shonnie was largely a creature of her environment.

Of Native American, Spanish, Jewish and, possibly, Chinese blood, she was born into a Catholic family who became Jehovah's Witnesses. Subject to periodic bouts with depression (she was molested at a young age), Shonnie was undoubtedly influenced by her childhood encounters with the penitentes, a brotherhood of lay Catholics who, anchored in their kiva-like moradas, practiced an intense hybrid of folk Catholicism and Native American rituals. As an adult, she had become a devoted Jehovah's Witness.

Painting Shonnie as a self-contained and somewhat childlike woman, unafraid to die, Wheelwright maintains that her involvement in a fringe religion likely made her more receptive to unconventional health care. Her iron-willed defiance may have also reflected deeper subliminal issues.

"Told what she must do," Wheelwright says, "she was the converso rankling before the Old Christian, the Indian resisting the españole, the Hispano resentful of the American, the Witness rejecting the world's authority while living within the world."

In the end, however, Shonnie, whose family is still torn over the decision she made, remains a puzzle, a reminder that there are things about human beings that can't seem to be explained by nature or nurture.