Book Chat: Carl Zimmer on the Potential and Perversions of Heredity

Science writer Carl Zimmer, a three-time winner of the AAAS Kavli Science Journalism Award, is the author of 12 books, the newest of which is She Has Her Mother’s Laugh: The Powers, Perversions and Potential of Heredity. The book, which will be available May 29, explores the history of heredity, how the concept evolved, what we actually do inherit through genes, and how new technologies and the cultures we inherit influence our future. 

Zimmer also writes the New York Times column “Matter,” and has contributed to the Atlantic, National Geographic, Time and Scientific American. Zimmer spoke with Kathleen O’Neil for AAAS, and their conversation has been edited for length and clarity.

AAAS: In your introduction, you talk about how you look for heredity in your daughters, and say that your oldest “has her mother's laugh.” How did you settle on that for the title?

Carl Zimmer:  I came up with the title before I had done very much on the book at all. I think I had been looking over some of the things I've been writing in recent years, and it occurred to me that heredity was the big idea that was lurking behind a lot of it. I just wondered what it was about heredity that was so mysterious and interesting to me. I think it's partly that we look at heredity as a big explanation about who we are, and we look for connections between ourselves and our ancestors. We have some almost magical thinking about heredity, so I wanted to explore that, and that whole history of what this word has meant to us.

AAAS:  New research is challenging our understanding of what we inherit and how, and how we can influence that. Can you tell us a little bit about that?

Carl Zimmer: Well, we do inherit genes, but our genes influence our traits in incredibly complicated ways, so you can't just look at some simple 23andMe report and figure out why you are the way you are in every detail. Given something as simple as how tall you are can be influenced by literally thousands of different genes, and all of those genes, you might inherit different combinations of different variants, and depending on how you grow up, they can make you kind of short, kind of tall, somewhere in between. And so, if something like height is so complex, then you really have to be very humble when we turn to other things like people's personality, or their intelligence and other things like that.

AAAS:  Toward the end of the book, you describe how a new understanding of heredity might help us address climate change. How could it?

Carl Zimmer:  In one of the later chapters, I explore culture as another form of heredity. We humans are very unusual compared to other species, because children learn from teachers, rather than just trying to imitate or observe them, and we have language. What all this means is that each generation doesn't just simply inherit genes, they inherit a whole culture. We depend on that culture to survive in all sorts of different environments.

So, each new generation of people is inheriting not just genes and culture, but also the environment that culture has reshaped. Fewer and fewer of us grow up in anything that you could call wilderness. And we aren't just modifying one area of farmland or another, but reshaping the entire atmosphere. The technologies that we build, the technologies that we pass down to the next generation then get modified as well. So, it's culture that's putting those greenhouse gases in the atmosphere, and it's going have to be culture that finds a way to take it out.

AAAS:  It seems like this was a more personal book than your previous ones—you discuss your family and some of your personal experiences. What made you decide to do that?

Carl Zimmer:  I've put myself in some of my books, but certainly not as much as this one. I think heredity by its nature is a very personal subject. I figured that rather than trying to make somebody else my guinea pig, I should open up my own story, and poke around, and talk about the things that I discovered just through my own experience.

AAAS:  Do you have any advice for science writers or others who are contemplating writing a book?

Carl Zimmer:  I think the most important thing to do when trying to write a book is to find a subject that you really, really want to write about, not a subject that you just think that other people might want to read about. You're going to be living with a book project for a long time, and so you really want to feel excited every time you come back to it. If you start feeling resentment, dread, it's going to really make it an unpleasant experience, and not a very good book.

I think that books are a good way to get across just how important history is to current science. For instance, people may not appreciate just how much danger there can be in using ideas about heredity to justify existing biases. If you go back and see how that happened in the 1800s and 1900s with eugenics, many of America's leading scientists were pushing for sterilization as a way of controlling heredity. You can see that the stakes when it comes to heredity are really high, and we can't just assume that the best kinds of decisions will always be made about it.

AAAS: How do you plan and write books regularly while also doing a column for The New York Times and writing other freelance pieces?

Carl Zimmer: It's not simple, but I've been doing this for a while, so I've learned the pace that I need to work at. So, for one thing, you just need to recognize that books often just take a long time, so in this case, I had a two-year contract for this book. As a freelance writer, I have the ability to turn the dials on different kinds of work, and so when I was really focused on my book, I stopped doing a lot of projects like magazine features, I took a break from teaching. The only thing I was continuing to do for a while there, was the column, in addition to the book.

I think the most important thing is to really try to work on it every day, because it's very tempting to say, “Oh, I'll get to it next week,” or next month. Books get written a little bit at a time, so you jut have to keep at it relentlessly.

AAAS: Did you finish it in two years?

Carl Zimmer: Yeah, it started looking a little doubtful, I had to admit, a few months before it was due. But my wife, who worked as a book editor for 10 years, intervened. She had me give her the manuscript as it was then. She went through it and gave me some good feedback about where I was veering off into stuff that really wasn't essential to the book. So, I was able to get it done on time.