The substance of what I'm interested in is that it's the genes that are related to behavior, and how they work. The big insight is that genes are the agents of nurture as well as nature. Experience is a huge part of a developing human brain, the human mind, and a human organism. We need to develop in a social world and get things in from the outside. It's enormously important to the development of human nature. You can't describe human nature without it. But that process is itself genetic, in the sense that there are genes in there designed to get the experience out of the world and into the organism. In the human case you're going to have genes that set up systems for learning that are not going to be present in other animals, language being the classic example. Language is something that in every sense is a genetic instinct. There's no question that human beings, unless they're unlucky and have a genetic mutation, inherit a capacity for learning language. That capacity is simply not inherited in anything like the same degree by a chimpanzee or a dolphin or any other creature. But you don't inherit the language; you inherit the capacity for learning the language from the environment.
THE GENOME CHANGES EVERYTHING: A Talk with Matt Ridley
"For the first time in four billion years," says Matt Ridley, "a species on this planet has read its own recipe, or is in the process of reading its own recipe. That seems to me to be an epochal moment, because we're going to get depths of insight into the nature of human nature that we never could have imagined, and that will dwarf anything that philosophers and indeed scientists have managed to produce in the last two millennia."
Ridley is an original thinker with deep insights who is in the top ranks of people writing about science. He also happens to be an English aristocrat who lives in Newcastle-upon-Tyne in a stately home on beautiful grounds. He embodies the best of that English tradition in that he uses his prestige, influence and his resources in the interests of science. Such patronage, and I use the term in the good sense, includes founding, and serving as chairman of the International Centre for Life, Newcastle-upon-Tyne’s science park and visitor centre devoted to life science. The centre is highly regarded for its serious research in genetics.
MATT RIDLEY'S 23 pairs of chromosomes, together with a doctorate form Oxford University, equipped him for a career as a science journalist with The Economist and the Daily Telegraph. His books include Nature Via Nurture: Genes, Experience, and What Makes Us Human; Red Queen: Sex and the Evolution of Human Nature; Genome: The Autobiography of a Species in 23 Chapters; Origins of Virtue: Human Instincts and the Evolution of Cooperation; and editor of The Best American Science Writing 2002.
He is chairman of the International Centre for Life, Newcastle-upon-Tyne’s science park and visitor centre devoted to life science. He has ingeniously combined his chromosomes with those of his wife, the neuroscientist Dr Anya Hurlbert, to produce two entirely new human beings. His books have been shortlisted for six literary awards. He has been a scientist, a journalist, and a national newspaper columnist. He is also a visiting professor at Cold Spring Harbor Laboratory in New York.
Ridley presents his latest book: Nature Via
Beyond Edge: Matt Ridley's Home Page
THE GENOME CHANGES EVERYTHING
the first time in four billion years a species on this planet
has read its own recipe, or is in the process of reading its
own recipe. That seems to me to be an epochal moment, because
we're going to get depths of insight into the nature of human
nature that we never could have imagined, and that will dwarf
anything that philosophers and indeed scientists have managed
to produce in the last two millennia. That's not to denigrate
what's gone before, but the genome changes everything. We know
that just because the first one or two glimpses inside this
box, the first lifting of the lid of the human genome, reveals to us
enormous insights into what's going on, and just from the first
few genes we're looking at.
of what I'm interested in is that it's the genes that are related to
behavior, and how they work. The big insight is that genes are the agents
of nurture as well as nature. Experience is a huge part of a developing
human brain, the human mind, and a human organism. We need to develop
in a social world and get things in from the outside. It's enormously
important to the development of human nature. You can't describe human
nature without it. But that process is itself genetic, in the sense
that there are genes in there designed to get the experience out of
the world and into the organism. In the human case you're going to have
genes that set up systems for learning that are not going to be present
in other animals, language being the classic example. Language is something
that in every sense is a genetic instinct. There's no question that
human beings, unless they're unlucky and have a genetic mutation, inherit
a capacity for learning language. That capacity is simply not inherited
in anything like the same degree by a chimpanzee or a dolphin or any
other creature. But you don't inherit the language; you inherit the
capacity for learning the language from the environment.
one important point is that genes are designed to produce human
behavior through nurture. But there's another phenomenon going
on too, which is equally important and which again people in
these kinds of debates over human nature have missed. They
couldn't have failed to miss it until recent molecular biology
made a difference. That is, behavior affects genes. It doesn't
change the code of the gene, and it doesn't change the encoded
genome. Sure, you can change your encoded genome by having
a mutational accident, by flying in an airplane and having
cosmic rays damage your DNA. But what I'm talking about is
changing the expression of genes through things you do in your
life. The encoded genome is a set of DNA. The expressed genome
is the RNA that's translated from it and then made into proteins.
That process of expressing the encoded genome is controlled
by transcription factors and all these other things that interact
with the promoters, which turn the genes on and off and turn
the volume of the genes up and down like thermostat switches,
or whatever analogy you want to use. That process is itself
at the mercy of the way we behave because you can do things
in your life that literally lead you to alter the expression
process of changing the strength of synapses between nerve
cells is mediated by genes. It actually requires the switching
on and off of genes in order to change the synapses. These
genes we now know, because of work on fruit flies, are called
the CREB genes. There are about 17 of them in that particular
system, and they're also in mammals and humans as well. They
prove that memory and learning is a genetic process. That doesn't
mean that it's a hereditary process—of course not. What
we're talking about here is changing the expression of the
genes in real life in response to what is literally the formation
of a new memory—a new experience, in other words.
doesn't fit into the wars between people on the nature side
and the nurture side very easily, and one of the things I've
tried to do is to get away from the idea of the nature-nurture
debate being a simple pendulum from one side to the other.
The important point about this argument is that it's empirically
driven. It starts with molecular biology. It starts with Seymour
Benzer and other people discovering the genes involved in learning
and memory; it starts with the discovery of real genes, and
what they're actually doing—the work of someone like Cathy
Rankin, a brilliant young scientist in Vancouver who has essentially
observed in real time the changes in the nematode as it learns
a new experience. She's done so by getting the genes to light
up, literally. The cells that are expressing this process light
up. She's also finding that those who have had a social upbringing
behave differently than those with a solitary upbringing—in
other words if they've been to school or been brought up at
home, if you like. These are worms, remember, nematode worms
with 302 neurons. Total. Maximum. No brains. And yet you can
see an effect of developmental upbringing, social upbringing,
etc., and it's these same synapses that are involved in the
process of learning and memory. Discoveries like that are driving
this new way of seeing the world, not theories. And to some
extent the theories have got to be a bit humble before the
new data. That's my epistemological position.
I find happens all the time in this debate is that you say
that there are genes involved in, let's say, sex differences,
and people say, "Oh no, no, no. Sex differences are social.
They've done an experiment that shows that sex differences
are socially caused." And I say, yes, sure, sex differences
are socially caused. I never said they weren't. I just said
there are genes involved too. Indeed, there are genes involved
in the social causation. That's the whole point. I don't actually
know how sex differences and behavior come about, and I don't
think anyone does yet. But it's pretty likely that what happens
is a form of prepared learning, whereby there is an instinct
for boys to end up one way and girls to end up another. But
the way that instinct works is for boys to have an instinct
to pick up from the world what boys do, not to arrive in the
world with a program in their head saying, "Pick up a stick
and go Pow! Pow! Pow! with it." It's "Ah, I like it when people
go Pow! Pow! Pow! with sticks. That fits with my perceived
way I'm heading in the world." Or I don't, according to which
gender I am.
Judith Harris has made an immensely important contribution in that she has blown the whistle on a huge mistake that's been made, which is to assume from the correlation between parents and children that children are learning things from parents. It turns out that once you control for heredity, through the use of behavior genetics, twin studies and adoption studies, you find that in the development of personality in particular—and that's quite a narrow point—children do very little learning from their parents, but they do quite a lot of learning from their peers. That seems to me a very important breakthrough. Judith Harris is building upon the behavioral genetics studies, where people like Thomas Bouchard and others with their studies of twins have made an immensely valuable contribution. But just because they're proving that genes are important in things like personality doesn't mean they're proving that environment is not important.
What it means is that they're proving that variations in family environment within a particular society don't change personality. It's a bit like vitamin C. If you don't get enough vitamin C it can cause a huge variation in your health, in this case scurvy. But as long as you're getting enough vitamin C, having extra vitamin C doesn't make you any healthier. And that's probably the way families are. You've got to have a sufficient level of love, affection, interest and stimulation from a family, but once you've got that, having extra doesn't change your development, whereas genes do vary all across the spectrum, and can change your development even in a constant environment. It's a bit like saying a kid with one toy in its entire life is obviously massively worse off than a kid with ten toys, but a kid with ten toys is not noticeably worse off than a kid with a hundred toys—or in my son's case, five million toys, as far as I can make out.
a lot of people who want the twin studies to go away. They
want them to turn out to be methodologically flawed. They want
to find that these twins knew each other all along, or that
somebody's faking the data—as indeed happened in the case
of Cyril Burt, as far as we can make out, although there are
some people who don't accept that. People who wish for that
are going down the wrong alley. The methodological criticisms
have run out of room to be any use. For example, people will
say that you can't learn anything from comparing identical
twins because identical twins have shared a womb. The point
is that a lot of the argument's answered by the fact that you're
also comparing non-identical twins reared apart, as well as
identical twins reared apart. And once you've got a decent
database of these things, you come up with these very strong
results saying that variations of personality within American
society are caused by variations in genes. Variations in intelligence
within American society are caused mostly by genes, partly
by family environment. These results are fantastically robust
now. They're not just from Bouchard's study in Minnesota; there
are also in the Virginia studies, the Australian ones, the
Dutch ones, and the Danish ones. There are big studies about
twins reared apart all over the world, and they're all coming
to the same conclusions, so it's no good wishing them away.
But the people who don't like these studies, and who wish them
away, are actually allowing them to be more powerful than they
are, because they're essentially thinking that they're proving
that genes are important at the expense of environmental factors,
and they're not. Often, the stronger the environmental factor,
the more genetic variation you're going to pick up.
very nice example of this, which is still quite a controversial
study, is Terrie Moffitt's work on antisocial behavior and
the mono-amine oxidase-A gene on the x-chromosome, which is
going to set the standard for how to understand the genes involved
in personality and behavior. I write about it in Nature
via Nurture. She's done a study of a cohort of New Zealanders
in Dunedin who've been followed ever since birth. All the kids
in this town were followed every year of their life to see
what happened to them. It's about a thousand kids. If you take
the 400 boys in the sample who have all-white genetic ancestry
up to the grandparent level—boys because we're talking
about a gene on the x-chromosome—and you look at their
mono-amine oxidase-A gene, and you look at whether it's the
high-active or low-active version—there are essentially two versions
of this gene according to how active they are, according to
whether the promoter on the front of the gene has got a certain
number of repetitions or a lesser number—does the less
active version of the gene correlate with ending up a young
adult who is antisocial and who's in trouble with the law?
No, it doesn't, in significant correlation. If you then break
the data down, though, into those who were abused in their
childhood and those who weren't, you find a very strong correlation
with this gene. It turns out that if you have the low-active
version of this gene, and you had an abusive childhood, then
you're going to end up with an antisocial adult—not deterministically,
but with a high probability. That seems to me to be a terribly
important study, because it shows that when you parcel out
the gene-environment interaction, you can find genes in here
that you wouldn't have found with the conventional gene-hunting
techniques—genes that correlate with behavior, but that
react to the environment.
If you go back to before the first two months of 1953, and ask yourself what people thought life was, you find nobody with anything like the right guess. Absolutely nobody is talking in terms of a linear digital code, until the morning of the 28th of February, 1953, when Jim Watson puts the base pairs together, and suddenly the idea of spelling out an infinitely long, infinitely variable, but completely faithfully reproducible code falls into place. You can say that Schrödinger used the term code script at one point, but he talked much more about quantum mechanical ideas and things like that. There were ideas that the secret of life was going to be some kind of piece of chemistry, a piece of energy, or a piece of quantum mechanics. There were all sorts of ideas out there, but nobody thought it would have anything to do with linear digital information, like we use in books, strings of alphabetical letters. That is why that is such an important moment, not because the thing was shaped like two spirals—that's just aesthetically pleasing—but because the world changed on that day. It took a long time for the world to realize it had changed, and Watson and Crick got invited to give zero seminars in Cambridge during the next three years, which is worth remembering, and there was nothing in the newspapers about it. 1953 was better known for many, many years as the year when Everest was climbed, the Queen was crowned, the first issue of Playboy was printed, and all these other tremendous anniversaries. But in retrospect we can see that it doesn't really click with the population at large until O. J. Simpson and Monica Lewinsky put DNA on the map in the '90s. It's forensic DNA, Alec Jeffries' discovery of DNA fingerprinting, that really brings it home to people what we're talking about here, which is a bar code, a message.
uncanny the way Turing and Shannon and all these people come
together with ideas of computability, digital information theory,
and cybernetics at around the same time as DNA falls into place.
Suppose the base pairing mechanism of the double helix had
been discovered in the 1920s, which is not totally impossible.
The x-ray diffraction stuff wouldn't have been possible, but
it's conceivable that a chemist could have worked out what
was going on in DNA without x-ray diffraction. In the '20s,
before computing, would we have even understood what we were
looking at? Possibly not. Would we have been able to imagine
one day reading it, and having the storage capacity to decode
it? Or the other way of looking at it then is to suppose that
DNA happens on schedule and we invent machines for sequencing
DNA, but we haven't actually got computers by the '90s. How
do we store the data? Do we have a lot of clerks writing it
down instead of computers? It is wonderful the way the two
branches of information technology, one called life and the
other called electronics, fall into place at the same time.
I don't understand how that kind of serendipity works in history,
but it's an intriguing one.
There's no question that the discovery moves in silicon now. In other words, a huge amount of the significant stuff that we do next has to be both understood inside a computer and modeled inside computers. The modeling of gene interactions is something that is beyond the power of a man with a pencil. It's going to require people who are good at systems dynamics. People who come out of business schools are quite good at this kind of thing. It's going to come from some funny directions. The economists are quite good at this kind of thing. The genome is going to turn out to be quite like an economy. When you adjust interest rates you have some effects here and other effects there, and then they have effects and they affect what affects interest rates and so it all feeds back on itself. A lot of genomic phenomena are going to turn out to be like that. So I do think that bioinformatics is the way a lot of this is going. You only have to look inside a molecular biology lab these days and see that they spend half their time comparing sequences on the Web with other sequences, pulling out sequences that are similar, saying, "Oh my goodness, this gene is like that one in fruit flies." But there's still going to be room for a lot of very important wet biology in this, particularly when you get inside the brain, because what's going to turn out is that the gross structure of the brain conceals immense amounts of detail about which nerve cells are talking to which nerve cells, and the genes are going to be the key to finding out what's going on there. These alternatively spliced genes that seem to enable each nerve cell to have almost a unique bar code on it that tells it who it needs to link up with when it gets to its target. There's still room for some heroic biology in there.