Weight doesn't just mean pounds.
If you want to answer the most existential of existential questions, don’t look at the historical record, look in a microscope.
The study of DNA has become so advanced in recent years “that it was transformed into a historical source,” writes geneticist Adam Rutherford. This has upended our understanding of human history and evolution.
In his new book, “A Brief History of Everyone Who Ever Lived,” Rutherford dispels myths about DNA (“there are people in your family from whom you have inherited no genes at all”) and clarifies concepts that were once beyond human understanding.
Rutherford joins us to talk about what we can learn from the 107 billion humans who have existed, and what this information can tell us about the next big question before us: where are we headed next?
- Adam Rutherford Geneticist; host, "Inside Science" on BBC Radio 4; author of A Brief History of Everyone Who Ever Lived: The Human Story Retold Through Our Genes
Why did you need to write this book now?
As a geneticist, talking to colleagues and talking to other geneticists, I found that I was having one set of conversations about fairly non-controversial things within academia, within science. And as a public communicator and a radio host, I found that I was having very different conversations. And you know, that felt like there was a disconnect there. Stuff that academics, stuff scientists think is correct, and stuff that the public generally think about genetics and inheritance. There was definitely a separation. I felt that that’s my responsibility. I’m meant to be the conduit between academic science and the public. So that was a big part of it. The second thing is that this book couldn’t have been written three years ago. The speed at which human history is being re-told using genetics, especially pre-history, is just off the scale. My publishers hate me because I was updating it days before the final deadline. And new papers are coming out every week, which means that I will be re-writing this book for many years to come.
What is the study of genetics all about?
It’s basically the study of sex and inheritance and families. And genetics is, as a science, it’s really only 100 years old. In any sophisticated form it’s really only 10 or 20 years old. And it’s changing at an unprecedented speed. But it turns out that people have been involved in families and having sex and thinking about inheritance for, well, the entirety of our existence. So that’s the sort of cultural baggage that geneticists are facing as our understanding of how our inheritance works. In some cases it contradicts what people for ten thousand years have been discussing.
How accurate are those mail-order DNA testing kits?
They are reputable, they are serious companies, and the data you’ll get back are robust. But it’s not necessarily what you think the tests are telling you. They give you broad sweeps of human migration, your genetic makeup, where it is shared with people on earth today. From that, you can infer some of your history. But it isn’t telling you where your DNA has come from. Broadly, these things generally affirm what we know about our own families. And if they don’t, they tend to simply affirm the fact that we are mutts. Humans are mutts. There are no pure lines, there are no pure breeds. People move around too much and have sex too frequently for us to remain pure in any way that could be recognizable by people who claim it.
What’s the deal with nature vs. nurture?
Almost all characteristics in humans are partly influenced by genes, and partly influenced by our environments. Francis Galton invented the phrase “nature versus nurture.” It’s not a useful phrase any more. A better phrase is “nature via nurture.” That’s what we say, more or less, in genetics these days. Because those two things are not in conflict. But what nature is, is your DNA, which is unchanging through your life. And what nurture is, is everything that is not DNA. And that’s one of the things where people get tripped up on this as a conversation. Because when you say nurture, people tend to think, “Well, did my dad give me enough cuddles, or did I go to this school or was I read to, blah blah blah.” It includes all of those things. But it also includes the orientation of the fetus inside your mother’s womb. It includes the cellular milieu that your DNA sits within. All of those things count as the environment. So when it comes to things like behavior, it is partly influenced by genetics and partly influenced by your environment. You gotta remember another thing– we inherit our environment from our families as well. So that’s non-genetic things that are passed in families because we experience them through our lives. Our environments are inheritable too.
Read An Excerpt
Excerpted from “A Brief History of Everyone Who Ever Lived: The Human Story Retold Through Our Genes” © Adam Rutherford. First published in North America by The Experiment. Available wherever books are sold.
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