Back in the pre-pandemic era, I was really looking forward to April 8. On that date, Carl Zimmer was going to give a talk at my school, Stevens Institute of Technology, about his latest book, She Has Her Mother’s Laugh. For decades, Zimmer has reported on biology in The New York Times and other publications and in books, 13 so far. Mother’s Laugh tells the epic tale of our attempts to plumb the mysteries of heredity and to improve ourselves with that knowledge. The book is a marvelous work of history—Zimmer’s account of the early days of eugenics in the U.S. is especially gripping—as well as a detailed, up-to-date report on CRISPR and other advances that add urgency to old debates about human enhancement. Zimmer is an engaging story-teller and insatiable reporter, who visits scientists in their labs and even volunteers to be a subject. As a result, while discussing the remarkable diversity of creatures dwelling on and in our bodies, he can tell you that his own bellybutton harbors a bacterium, Marimonas, also found in the Mariana Trench. In lieu of Carl’s April 8 talk, here he answers questions about genetics and related topics. – John Horgan
Horgan: How did you end up in the science-writing racket, anyway? Any regrets?
Zimmer: I feel incredibly lucky to have this job. It wasn't anything I thought about with any foresight. I loved to write, and I loved science. A couple years out of college, I got a job as an assistant copy editor at the science magazine Discover. There, I got a great training in how to fact-check and report on science. I stayed there for ten years before heading out on my own.
Horgan: Why the focus on biology? When you started out, wasn’t physics going to solve everything?
Zimmer: As a junior reporter at Discover, I had to write about all sorts of stuff--astronomy, geoscience, physics, technology, and so on. But I found that biology was always the field that managed to surprise me the most. Evolution has gone off in such crazy directions in the past four billion years, and the tools biologists have to study life have grown incredibly powerful over the past few decades.
Horgan: I sometimes worry I’m too mean to scientists. Do you ever worry you’re too nice?
Zimmer: As a fact-checker, you learn that no one should be given a pass. When I report on a story, I talk with outside experts to see if researchers I'm writing about are really delivering on what they claim. And it's also important to keep up with what social scientists and philosophers have to say--because science doesn't happen in a vacuum and can have dangerous consequences.
Horgan: What’s the biggest thing that’s happened in science since you started writing about it?
Zimmer: DNA sequencing. It changed everything, from the study of Neanderthals to tracking the covid-19 pandemic.
Zimmer: No. Creationists have not done any good science since then, while evolutionary biology has leapt forward in dramatic fashion.
Zimmer: People try to deflect from weak arguments by accusing their opponents of being contemptible.
Horgan: Is CRISPR living up to its hype? If so, will it help gene therapy, finally, take off?
Zimmer: CRISPR is already a mainstay of scientific research, for testing how genes work and how mutations affect health. It's already into clinical trials for diseases like sickle cell anemia just few years after its invention. We have yet to see how well it will work in those applications. But it's unquestionably one of the most important advances in the history of biology.
Horgan: By the time I reached the end of She Has Her Mother’s Laugh, I wasn’t sure whether you think genetic enhancement of humans is feasible, or desirable. Could you clarify?
Zimmer: I think anyone who pretends to have a simple answer is wrong. The answer depends not only on the complexity of biology, but also on what we really want from genetic enhancement. We are already carrying out genetic enhancement when parents with Huntington's disease pick embryos for IVF without the mutation. But I'm skeptical that any manipulation will affect, say, intelligence--certainly not more than what a decent education and a healthy childhood can offer.
Horgan: Will there be any more revolutions in our understanding of heredity?
Zimmer: It's not possible to predict revolutions that haven't happened. But I think that scientists will learn a lot about how epigenetic changes can be carried down through generations--if not in humans, then in other animals and plants.
Horgan: Will our knowledge ever be so complete that the nature/nurture debate finally ends?
Zimmer: I can't rule it out, but it won't be easy. It's relatively easy to study how genes influence variation, but the environment is so vast and complex it may not submit to simple experiments with clear results. Still, there are some very impressive experiments that are grappling with these challenges.
Horgan: Are radical life extension, and possibly immortality, feasible?
Zimmer: I'm not holding my breath. Aging is the result of so many factors that it's hard to see how any simple intervention can change it much. Immortality just seems biologically silly to me.
Horgan: I can’t resist asking: what do you think of the U.S. response to the coronavirus?
Zimmer: A disaster.
See also my free, online book Mind-Body Problems: Science, Subjectivity & Who We Really Are, also available as a Kindle e-book and paperback.