The Gene: An Intimate History - Siddhartha Mukherjee Page 0,3

emerged with a sudden, surprising force, as if he were spitting out strange pips of food that had been put into his mouth. He had little memory of my father, or me. When I mentioned my sister’s name, he asked me if I had married her. Our conversation proceeded as if I were a newspaper reporter who had dropped out of the blue to interview him.

The most striking feature of his illness, though, was not the storm within his mind, but the lull in his eyes. The word moni means “gem” in Bengali, but in common usage it also refers to something ineffably beautiful: the shining pinpricks of light in each eye. But this, precisely, was what had gone missing in Moni. The twin points of light in his eyes had dulled and nearly vanished, as if someone had entered his eyes with a minute paintbrush and painted them gray.

Throughout my childhood and adult life, Moni, Jagu, and Rajesh played an outsize role in my family’s imagination. During a six-month flirtation with teenage angst, I stopped speaking to my parents, refused to turn in homework, and threw my old books in the trash. Anxious beyond words, my father dragged me glumly to see the doctor who had diagnosed Jagu. Was his son now losing his mind? As my grandmother’s memory failed in the early eighties, she began to call me Rajeshwar—Rajesh—by mistake. She would correct herself at first, in a hot blush of embarrassment, but as she broke her final bonds with reality, she seemed to make the mistake almost willingly, as if she had discovered the illicit pleasure of that fantasy. When I met Sarah, now my wife, for the fourth or fifth time, I told her about the splintered minds of my cousin and two uncles. It was only fair to a future partner that I should come with a letter of warning.

By then, heredity, illness, normalcy, family, and identity had become recurrent themes of conversation in my family. Like most Bengalis, my parents had elevated repression and denial to a high art form, but even so, questions about this particular history were unavoidable. Moni; Rajesh; Jagu: three lives consumed by variants of mental illness. It was hard not to imagine that a hereditary component lurked behind this family history. Had Moni inherited a gene, or a set of genes, that had made him susceptible—the same genes that had affected our uncles? Had others been affected with different variants of mental illness? My father had had at least two psychotic fugues in his life—both precipitated by the consumption of bhang (mashed-up cannabis buds, melted in ghee, and churned into a frothing drink for religious festivals). Were these related to the same scar of history?

In 2009, Swedish researchers published an enormous international study, involving thousands of families and tens of thousands of men and women. By analyzing families that possessed intergenerational histories of mental illness, the study found striking evidence that bipolar disease and schizophrenia shared a strong genetic link. Some of the families described in the study possessed a crisscrossing history of mental illness achingly similar to my own: one sibling affected with schizophrenia, another with bipolar disease, and a nephew or niece who was also schizophrenic. In 2012, several further studies corroborated these initial findings, strengthening the links between these variants of mental illness and family histories and deepening questions about their etiology, epidemiology, triggers, and instigators.

I read two of these studies on a winter morning on the subway in New York, a few months after returning from Calcutta. Across the aisle, a man in a gray fur hat was pinning down his son to put a gray fur hat on him. At Fifty-Ninth Street, a mother wheeled in a stroller with twins emitting, it seemed to my ears, identically pitched screams.

The study provided a strange interior solace—answering some of the questions that had so haunted my father and grandmother. But it also provoked a volley of new questions: If Moni’s illness was genetic, then why had his father and sister been spared? What “triggers” had unveiled these predispositions? How much of Jagu’s or Moni’s illnesses arose from “nature” (i.e., genes that predisposed to mental illness) versus “nurture” (environmental triggers such as upheaval, discord, and trauma)? Might my father carry the susceptibility? Was I a carrier as well? What if I could know the precise nature of this genetic flaw? Would I test myself, or my two daughters? Would I inform them of the results? What if