How DNA Is Reshaping How We See Ourselvesand Our History

In her early 20s, Christine Kenneally discovered something about her Australian forebears that upended her sense of identity and family history. In her new book, The Invisible History of the Human Race: How DNA and History Shape Our Identities and Our Futures, she explores the power of DNA to reveal secrets in our past and predict our future.

Talking from her home in New York, she explains how even the moistness of our earwax is encoded in our genes, why our decisions are not entirely our own, and how the genetic imprint of distant historical events like slavery can shape attitudes today.

The book begins with you flying to Australia, about to discover a long-kept family secret. Tell us about the Kenneallys.

I kept circling around this memory from when I was in grade two, about eight years old. Our teacher explained what a family tree was. I was completely bewitched by this idea. I thought it was magical that you could see these lines through your familywho came from whom.

So I ran home excitedly to ask my parents what the names of my grandparents were. I was really surprised by their response. They were not happy about it. In fact, they were kind of indignant. Their attitude was: What business is it of your teacher to ask these sort of things?

Many years later, when I was in my early 20s, we were having a conversation around the kitchen table, and my father told us that the person we thought of as our grandfather was really his grandfather. And that the woman he'd grown up thinking was his sister was really his mother. And that he didn't know who his father was.

It was an incredibly significant moment in our lives. Not for the reasons I think my father feared. He came from a generation when illegitimacy was a terribly shameful thing. But this was the late 20th century. We didn't have any of those feelings. But we did feel this shuddering in our identity. The thing we'd always thought was true was not true. That's what connected with me with these questions I had about how our identities are builtwhat gets passed down to us over the years. And what can you ever really know?

You write that "the question that came to concern me, and that lies at the heart of this book, is how many decisions and how much of our self-knowledge are ultimately path dependent." Unpack that idea for us.

We have this vision of ourselves as completely in control of who we are in any one moment, as essentially creating ourselvesat least once we've become adults.

But there are many traits we have and many decisions we come to that are shaped by paths we've taken in our lives and by paths our ancestors have taken.

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How DNA Is Reshaping How We See Ourselvesand Our History