Steve Jones on Extinction [1]

STEVE JONES:  Thanks for that. I come in as the bearer of an apparently almost extinct genetic signature, which is the Y chromosome, so it’s appropriate that I should read last on the list. That's all I’m going to be talking about. I’m going to be talking about extinction in the human sense, about the way in which human differences across the world are very quickly eroding away. It’s well known, the famous phrase, "No man is an island, no woman is an island either." Nowadays as we’ve heard in the last talk, "No island is an island because everything is being homogenized." The Galapagos, for example, many of their creatures have been driven to extinction by other creatures that come in from outside by migration.

What I wanted to talk about is somewhat of a parallel of that in human populations. If you were to go to a textbook on human biology from the time of Darwin or a bit later, you would certainly get an image that looked a bit like this. This is an image of the so-called races of humankind—racial types, as they called them. I’m not going to go into the question of whether there are real races of humankind because there aren’t. It’s interesting to note that until quite recently people assumed, and scientists assumed too, that the human species was divided into distinct groups that were biologically different from each other and had been isolated from each other for a long, long time.

Well, to some extent that was true. Until quite recently, human populations were isolated from each other. That’s changing quite quickly. I can illustrate that perhaps by a simple experiment. Can you shake hands if you don’t mind? You don’t have to. Can you shake hands with one of the two people next door to you? For about half of you, I have just introduced you to your sixth cousin. That’s a surprising fact, but it is true. What I’m saying is that for about half of you, two of you shared an ancestor who lived at about the time when the Origin of Species was written in 1859 and when Darwin went to the Galapagos.
For a population like the modern British population, or the modern European population, we are it might seem, more closely related to each other on average than you might have imagined. Were I to be giving this talk in Pakistan—which I probably wouldn’t go down particularly well—if I were to do the experiment again, for about half of the people shaking hands, they would be shaking hands with their first cousin. They would be shaking hands with somebody who shared an ancestor with them who was alive during the Second World War.  

What that tells us is that the European population is much more open in biological terms, much more admixed, as we would say, than our populations say in Pakistan where people don’t move very much. They tend to marry within groups, and families stay closed within families. That effect is quite striking. Pakistan is much more inbred than Britain, and the question is what is going to happen in the future. Are we going to remain as these isolated groups, as some places still are, or are we going to become even more admixed?
We can put some figures on how inbred—how closely related—we are bound to be. Let me show you a picture of the end of the world. This is the apocalypse according to William Blake. As we all know, if we've read the book of Revelations—clearly written by a paranoid schizophrenic—it’s filled with terrifying things that are going to happen at the end of time. Everybody who has ever lived will come up from the grave and will stand ready for judgment on the plain of Armageddon. It will be decided whether they are good or evil. Good people, a very small proportion, will go to heaven. Everybody here at the Serpentine Gallery is clearly a good person, so you’re all safe. If you were to go, for example, to the Frieze Art Faire, you would certainly burn in hell for the foreseeable future.
Now that’s an interesting story because it has a reflection from history. Here we have a picture of Armageddon itself. This is the Israeli city in northern Israel called Megiddo. It’s now a tell; it’s now under excavation, I’ve been there. Megiddo was a thriving city in Israel, which was destroyed in 722 BC by King Sargon of the Assyrians, who came in like a wolf on the fold and destroyed the city, killed lots of people, and drove the rest into exile.
The people of Megiddo generated a myth, quite a common one, that someday in the future they would be reunited. The lost tribes of Israel will come together Har Megiddon in Megiddo on the plain. That’s where this idea of Armageddon comes from. Well, this happened in 722 BC, so let’s count how many people would be at the event if everybody who had lived was to be there.
We all know that we have two parents, each one of us, four grandparents, most of us, eight great-grandparents, 16, 32, 64, 128, 256. If that were the case all the way back to 722 BC, how many people would be assembled ready for judgment? Here’s the sum: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096. I used to do this when I was eight in the bath. Little did I realize I’d spend my life doing it. You would have approximately 100,000,000,000,000 (a hundred million million) supposed ancestors, which would be more than enough to cover the whole surface of the earth two or three people thick. What that tells us is we have to share ancestors. We have to be inbred because there’s no room on the family tree. We are all related to each other to some degree.
In fact, everybody in the world descends from somebody who lived approximately in 4,000 BC, which interestingly enough is the biblical estimate of the time of the Garden of Eden, but that’s another story. However, the extent to which we share ancestry differs very greatly from place to place and is changing very, very quickly, which means extinction for lots of, at the moment, separate groups.
Now, how are we going to study this? One way we can study it of course, is by looking at pedigrees. As you perhaps heard at the introduction, I’ve wasted my life by working with snail populations and genetics. I’m one of the world’s top six experts on snail population genetics. The other five tend to agree; there aren’t many of us. I’ve also worked on fruit flies and I’ve even lured myself to work on humans.
Now there is a human equivalent of the humble fruit fly, which is of course the royal family. Royal families are wonderful for genetics because they are defined by pedigrees, so they keep an account of how many ancestors they have. If you look at particular royal families, they’re often very, very separate from each other because they marry within themselves. Perhaps the classic example is the royal family of Spain.
Let’s take, for example, Alfonso XII, who was the king of Spain in the 19th century. Alfonso XII married Ena, who was Queen Victoria’s granddaughter, and she, Ena, brought in the famous hemophilia gene to the family. That’s another story. If we were to do the rules for Alfonso XII and go back for seven generations, he should have 2, 4, 8, 16, 32, 64, 128 different ancestors seven generations back.
But if we look at the pedigree, it turns out that seven generations back he had only eight ancestors. That’s because it was cousin marriage after cousin marriage after cousin marriage. That was true for plenty of people. It’s fortunately for us less true for the royal family, who lives just that way down the road. They’re rather outbred. But plenty of royal families are inbred, and if you look at their pedigrees in more detail what you get is lots and lots of loops—people marrying their relatives. That’s still very common.
Another way you can look at patterns of isolation is to look at a particular attribute, which is inherited and which is easy to study and is very cheap to study because all you need to study it is a phone book—the surname. There’s a whole area of genetics which works on the biology of surnames—second names in the European system—passed from father to son and to daughter but daughter’s change or changed their names on marriage.
This was discovered by the chap who founded our own laboratory at University College London, Francis Galton, who was Charles Darwin’s cousin and the founder of that rather dubious science called eugenics. Galton was a highly talented man and interested in many things. He was interested in human quality most of all. He made, as far as we know, the only beauty map of the British Isles ever made based on the little brass counting device he held in the palm of his hand and went from city to city counting the local females on a five-point scale from attractive to repulsive. The low point was in Aberdeen and the high point, you’ll be glad to learn, was in South Kensington, just here, so not much has changed.
That’s an eccentric thing to have done, but he did more interesting things than that. He had the habit of going on walking holidays in the Italian-speaking part of Switzerland—very poor, very isolated mountain villages. He went one year and settled down in a little village. He discovered something very strange, which was that everybody in that village— prepare yourself for a terrible joke—had the same second name. They were all called Spaghetti.
He climbed over the mountains to the next village, settled into the inn, asked people what their names were. Everybody had the same name, but it was a different one—Pasta. In the next village—Cannelloni, and so on. This for the moment made him think that this was because it was advantageous to be called Spaghetti in village One and Pasta in village Two, but after a moment’s thought that showed it wasn’t true. It turned on the fact that people within the village married somebody else from the village. If he looked into the pedigree of the village, ten generations ago there was a family called Pasta, a family called Spaghetti, a family called Cannelloni. But each generation now and again a man had no sons, so his name disappeared. In time one name took over. What you can do is to look at isolation by asking how many surnames there are in a particular place in relation to the number of people. By doing that, you’re asking how many Y-chromosomes there are in a particular place.
Here’s a map of Britain, rather perverse because it’s altered in terms of population number. The warmer the colors, the more surnames there are in relation to the number of people. You can see London, which is nice and warm, has lots and lots of surnames in relation to the number of people. West Wales, which is where I come from, is blue and cool. It’s cool in many ways, but it’s cool in the surname way, which means that there aren’t many surnames in relation to the number of people. The northern islands of Scotland are even cooler; there are very few surnames in relation to the number of people. In other words, people are staying within their own group. They’re marrying within their own group. They’re keeping a biological identity. Now that’s interesting in many ways. It means you can immediately tell yourself by looking at the New York phone book say that New York is a much more mixed and outbred population than, say, Oslo. In fact, the mean number of surnames, people per surname in the New York phone book is two-and-a-half. In Oslo it’s sixty because again, a much more isolated population.
That’s important, not just because of curiosity, it’s important in health terms. If you look at the patterns of outbreeding and inbreeding across the world, you can see that some populations remain strongly isolated and separate from others within the same area. The warmer the color, the more inbreeding. You can see, for example, in Pakistan, which I’ve talked about, the extent of cousin marriage is so high and the extent of uncle-niece marriage is so high, which is even closer, that people are very closely related to each other within particular populations.
In Britain it’s much less, in North America it’s much less again. That has an effect on health. This is the patterns of mortality and morbidity of children. In Branford, British Pakistanis versus the European population of Branford, you can see there’s about a doubling in the mortality and morbidity of children. It’s important from the point of view of medicine. People in Branford are now more and more aware of this and there are attempts to reduce the amount of cousin marriage, which has not being particularly successful.
It’s also interesting from the point of view of evolution. We know very well from fossils that humans, we’re all Africans. We got out of Africa maybe 80,000 years ago and spread across the world, getting to the new world only about 20,000 years ago. If you look across the world from our birthplace in Africa and ask how much variation is there within particular populations, it turns out that—the red lines are the tracks which we walked across the world, roughly speaking—if you measure the distance from Addis Ababa, walking distance, you get this amazing fit between the amount of genetic variation in a particular population and the distance from birthplace. That’s because, as we moved, we were inevitably in small, inbred groups. If you go into Europe let’s say, quite close to Africa, we’re not particularly invariant. If we go to Eastern Asia, less variable again. If we go to Oceania, places like Tahiti or the Southern tip of South America, we’ve lost about a third of our genetic variation. That tells us over history we’ve been rare animals and the further we’ve moved away from our homeland, the more reduced we’ve become and the more different these populations are for purely random reasons from their ancestors.
The question then arises: What of the future? Well, in fact, we’re in a moment in which we’ve reversed the processes, which have driven human evolution since it began. First of all, there’s very little natural selection anymore, although that’s a different story. But second and more important, we’re no longer in most places doing this business of marrying people which we are related to.
In London, which is a very outbred city, among young children under 10 in London who’ve got one Afro-Caribbean parent—mother or father—the other parent—father or mother—is white European. That barrier, based on the genetics of skin color, is breaking down very quickly. Interestingly enough, what determines who you will marry in London is not your skin color but overwhelmingly it’s your educational level. Education level, whether you’ve both got degrees or one’s got a degree and one left school at 16, education level is five times more important in choosing a mate in London than is skin color, so those barriers are breaking down.
We can see in other ways how that’s happening. What we can do, we can ask a simple question, and I’ll ask you to ask yourselves this question. How far apart was the birthplace of yourself and your partner, if you have one, compared to the birthplace of your mother and father, your mother’s mother and your mother’s father and so on? I can guarantee for almost everybody that that figure has enormously increased in just two or three generations.
Mine’s a bit extreme. My wife was born in New York, 3,000 miles away. My parents were born in West Wales in two villages three miles apart. I once gave this lecture and a student at the back shouted, "And it shows!" I hope it doesn’t. The marriage distance can tell you something too. The surnames, the reason is of course that people are beginning to move. You no longer have to marry the boy or the girl next door; you can get on your 747 and marry the boy, or the girl, from the other side of the world. In some ways, perhaps the most important event in human evolution was the invention of the bicycle or indeed the 747, which is bringing the peoples of the world together and getting rid of these patterns of small isolated groups.
I’ll just end up by showing another clue which shows how powerful, important, and advantageous this effect is. This is a map of the surname, my name, Jones in 1881. You had to make one percent of the population to get onto this map. You can see we were tucked away behind Offa’s Dyke in Wales. Here’s the figure of Jones in 1998 and the Jones’s are on the move. We’ve got to Oxford. We haven’t got to Cambridge yet. And that’s true of everybody. There’s an enormous movement and mixture of names and of genes.
What's happening to our species is that there is extinction, but I look to that, unlike the extinction in the animal world, as being a very positive effect and not a very negative one. I do hope you agree with me.

Thank you.