Dani Shapiro has built a career writing about the perplexing corners of her life — the mysteries of her marriage; the discomfort she felt as a child who never quite fit in; the quandary of growing up in a strict Orthodox Jewish home but never connecting with her faith. In memoir after memoir, she has sifted through her memories, questioning everything.

Could the answers have been in her DNA all along?

In her fascinating new memoir, "Inheritance," Shapiro sends off a sample of DNA to be analyzed, mainly as a lark. After all, she knew who she was: The daughter of the very difficult Irene Shapiro and the beloved, sadsacky Paul Shapiro, both Ashkenazi Jews from New York. Her father, in particular, defined her — she grew up with his legends and stories; his well-worn prayer shawl, which she gave to her own son; and framed photographs of his ancestors, "small, wiry, dark-eyed people of the shtetl, the men swaying over crumbling tombstones, prayer books in their hands."

There had been hints that things were not quite what they seemed, but she had never paid them any mind. It's easy, she notes, to ignore clues when you think you already know the truth.

"I was the lone pale, blond child in the sea of dark-haired, dark-eyed grandchildren," she writes. "Yet I never had any doubt that I was part of the chain that reached back and back through the generations, unbroken."

Her mother had once dropped the odd fact that Dani — an only child — was conceived in Philadelphia, but when pressed said only, "Oh, you don't want to know. It's not a pretty story."

Inheritance, by Dani Shapiro

So when the DNA test results came back telling Shapiro that she was only 52 percent Ashkenazi Jew, and the other 48 percent was a mix of French, Irish, English and German, it was a bombshell. It had never occurred to her, not once, that her parents, now dead, weren't who she had always believed them to be.

And so begins a remarkable, dogged, emotional journey as Shapiro digs into the past to find the truth.

"Inheritance" reads like a mystery, unfolding minute by minute and day by day. The reader experiences the grief, surprises and setbacks right along with the author.

Even as she is devastated, it's clear that Shapiro is, in some ways, excited by this puzzle. "What never fail to draw me in," she writes, "are secrets."

She and her husband, journalist Michael Maren, are a formidable team as together they figure out who the biological father was, and where — and why, and how — in Philadelphia the conception took place.

Shapiro wrestles with unanswerable questions (What did her mother know? What did her father know? Did they lie to her? Did they lie to each other?) as well as philosophical ones (What is paternity? What is family? What is legacy?). She also deals with more practical issues — should she contact her biological father, who almost certainly doesn't know she exists? Should she tell her own son that his grandfather is not really his grandfather?

She juggles all of these threads and — it must be said — all of this overwhelming emotion quite deftly, while spinning the story out smoothly. She seeks answers from everyone who might have a glimmer of information: her father's ancient sister, his rabbi, doctors, scientists, DNA experts.

The question of what makes a person a parent has always been complicated, with adoptions and divorce and family members raising children when biological parents cannot or will not. Is your father the one who sired you? Or the one who raised you?

Some of these secrets were never meant to be uncovered, but DNA testing has changed the rules. Shapiro's book is a wise and thorough examination of how this news affected her. She is a good guide for the bombshells that are yet to explode for so many families.

Laurie Hertzel is the senior editor for books at the Star Tribune. 612-673-7302 • www.facebook.com/startribunebooks

Inheritance
By: Dani Shapiro.
Publisher: Alfred A. Knopf, 272 pages, $24.95.
Event: In conversation with Nora McInerny, 7 p.m. Jan. 28, Modern Well, 2909 S. Wayzata Blvd. $30; includes book. Click here to make reservation