SCOTT SIMON, HOST:
Genealogy has become an enthusiasm and an industry. Give us a lick of your saliva. We'll trace your roots. The people who thought they were purely European discovering a dollop of African ancestry, people with African ancestry finding in the village of their forebearers and lots of people discovering that almost all of us are mixed up one way or another.
A.J. Jacobs says there may even be a world family tree that includes us all. His book - "It's All Relative: Adventures Up And Down The World's Family Tree." And my cousin, A.J. Jacobs, who is often on this program to cravenly promote his best-selling books and is ostensibly an editor-at-large of Esquire, joins us from New York. Thanks so much for being with us, cousin.
AJ JACOBS: Thank you, cousin Scott.
SIMON: You know, under NPR's ethical guidelines, I can't interview family members to promote a book.
SIMON: So, A.J. Jacobs, thank you very much. This is NPR News.
JACOBS: (Laughter). Understood. Listen. You've got obligations.
SIMON: But let's just continue anyway. How many relatives have you discovered you have?
JACOBS: Oh. I'd say 6 or 7 billion. The point of this book is this revolution in genealogy. And that is showing that we are all related, which I guess we knew since we were kids. You know, we're all family. But now we can see it concretely. And it's kind of mind-blowing.
SIMON: Yeah. Adam and Eve aren't just biblical characters, are they?
JACOBS: Right. I don't believe in the literal Adam and Eve 5,000 years ago in a garden. But scientists talk about Y chromosomal Adam and mitochondrial Eve, who lived probably about 200,000 years ago. And we all have a little bit of their DNA in us. So you, me, Miley Cyrus, the guy who stole your parking space at Chipotle - everyone.
SIMON: A timely discovery. Donald Trump and Robert Mueller may be related.
JACOBS: Yes, I'm afraid so. They - pretty much the amazing thing about this world family tree is that you can find how anyone is related. So this is - it's done through DNA testing and through the internet - this sort of a Wikipedia model of family trees. So thousands of people working on the same family tree. And it's not just thousands of people on the tree. It's millions. Right now the biggest is about 200 million people all connected. So for instance, Barack Obama is my fifth great aunt's husband's brother's wife's seventh great nephew - so practically my brother.
SIMON: Had that been known before the election...
SIMON: ...It would've stood no chance.
SIMON: My gosh.
JACOBS: And you and I, Scott...
JACOBS: I actually did figure out that...
SIMON: We are cousins - I forget how many hundreds of times distant from each other.
JACOBS: (Foreign language spoken). I'm sorry...
SIMON: Actually, a little closer than that, right?
JACOBS: Oh, yeah. Well, you are part Jewish, if I'm not mistaken...
SIMON: Yes. Right.
JACOBS: ...Which means that we are actually quite close. The average Jew is probably about six or seventh cousins from another Ashkenazi Jew. So you and I are quite - we are mishpocha. You've got to come over for Passover.
SIMON: (Laughter) Thank you. Thank you very much. And you have to join us for Easter.
JACOBS: Deal. Well, I do have - I have - you know, when I took the DNA test, it was interesting because I got to see what you said earlier - that we are all a mix. I found I am mostly Jewish. I'm - according to one, I'm 97 percent Jewish and 2 and a half percent Arab. So I have the Middle East conflict in my body. My hope is that the more we reveal we are mixed, the less tribal we will be. And one of the - one of my favorite results that's already happening is that white supremacists are taking the test, finding out that they're not purely white and freaking out. And I just love their discomfort.
And there's a study by some UCLA professors on the reaction on these "alt-right" websites. And some of them are denying it. They say, no, this is a multicultural conspiracy by the genetics companies. But I think, eventually, they're going to have to face up to the fact that racial purity is kind of a myth. My hope is that we realize that we are all - like we were told these kids, we're all one big family, but now we can see it really concretely.
SIMON: It's not just a Disney song.
JACOBS: It's not a Disney song. And there is no such thing as racial purity. But more than that, there's no such thing as species purity. We are a mix of species. So your 2000th great-grandpa or grandma was a Neanderthal. So we are mutts. We are full-on mutts.
SIMON: A.J. Jacobs - his book - "It's All Relative: Adventures Up And Down The World's Family Tree." Cousin A.J., so nice to be with you.
JACOBS: Thank you, cousin Scott. Transcript provided by NPR, Copyright NPR.