What makes you you?
Prof. Dr. Ing. IPS Raspopitul Esq.
* 19 August 2006
* NewScientist
* Dan Jones
If you are looking for deeper self-knowledge, forget introspection and
put your faith in science. Not only will it tell you about your health,
it can also reveal secrets about your ancestry, personality, sexuality,
attitudes, perceptions and intelligence. In this special report, New
Scientist gives you the latest developments in the study of
individuality, starting with what promises to be the richest ever
source of self-knowledge - your own genome. This should be available to
you in a few years, but what will it tell you about yourself, wonders
Dan Jones
CRAIG VENTER can make a unique claim. "To my knowledge I am the only
person on the planet to have their genome decoded," he says with a hint
of satisfaction. He is the driving force behind the commercial effort
to sequence the human genome, so it is perhaps not surprising he was
the first to attain this level of self-knowledge.
He hopes he will not be alone for long. The J. Craig Venter Science
Foundation is sponsoring a $10 million prize for anyone who can get the
cost of sequencing an individual's genome down to $1000. Venter
predicts it will be scooped within a decade. At this price, plenty of
people will be able to unravel their personal genetic story. "That's
when we're going to see a massive shift in the study of human genetic
variation and our own personal genetic make-up," he says.
Venter believes that once geneticists can compare thousands or even
millions of individual genomes, they will get a better handle on why,
as individuals, we turn out the way we do. Already we can link certain
genes with diseases, personality traits, cognitive styles, aptitudes
and the like. And although Venter does not believe in genetic
determinism - the view that our fundamental nature is written in our
genes - he still champions the importance of genes. "We're clearly not
born blank slates, but I think the genetic effects on these traits are
a lot stronger than most people are willing to deal with." Venter
thinks that the analysis of entire personal genomes, together with
information about how people actually live their lives, will provide a
whole new window onto the complex interplay between your nature and
your nurture. This avalanche of genomic knowledge could render the
Freudian revolution a footnote of intellectual history. And unlike
psychoanalysis, it might even give you the information you need to
ensure your kids reach their full potential.
"The genetic effects are stronger than most people are willing to
deal with"
Some readers will find this prospect tremendously exciting, others
quite terrifying. The fact is, though, that if Venter's dream is ever
to become reality, a lot of people need to get their DNA sequenced. To
get the ball rolling, Venter plans to unveil his genomic portrait on
GenBank, the US National Institutes of Health genetic sequence
database, making it freely available to anyone. Perhaps you are tempted
to join him. If so, before you shell out the cash, you will probably
want to know what you will be getting for your money. Put plainly, will
you attain a level of self-knowlege previously unknown to humankind, or
will your genome tell you little you didn't already know?
Do you really want to know?
The most obvious benefit of genomic knowledge is in predicting if and
when you are likely to succumb to illnesses such as heart disease,
stroke, Parkinson's and diabetes. Armed with this information, you
could decide to take preventive medicines, or make lifestyle changes to
delay or stave off the development of a condition. In a decade, we will
undoubtedly know far more about how certain versions of various genes
are linked to particular conditions. Venter, unsurprisingly, is ahead
of the game. A look through his genome has prompted him to start taking
cholesterol-lowering drugs called statins to delay or prevent heart
disease.
Such insight sounds attractive, but it also raises the thorny issue of
how to deal with information about your chances of future health,
particularly as medical professionals might not be on hand to provide
their interpretive and counselling skills. In a few cases the
implications of finding a certain mutation will be certain. People with
a particular duplicated region of chromosome 4, for example, always
develop Huntington's disease. More often, though, the link between a
sequence of DNA and any disease it might contribute to is much less
clear-cut, often depending on the combined effects of many genes and
environmental factors.
This goes to the heart of the main problem with personal genomics. Gone
are the days when people talked about "the gene for X". Rare cases like
Huntington's aside, at best all we can say about most sequences of DNA
is that they confer on carriers a certain likelihood of developing a
particular condition or trait. For example, a genetic variant could
have a harmful effect in 70 per cent of people, but no detectable
effect in the remaining 30 per cent. "Understanding this whole field
will come down to probability statistics, which are very hard to
interpret," admits Venter. In essence, the vagaries of genetic
prediction mean that some people might benefit greatly, and others not
at all.
The problem of probabilities is even greater when trying to understand
the genetic basis of aspects of personality, temperament and
intelligence than for many health-related traits. The details of human
behaviour are not spelled out in the genome; social and cultural
factors profoundly influence how we think and act. That doesn't render
genes irrelevant. Genes are crucial to the development of the mind,
personality and behaviour, just as they are for building limbs, lungs
and livers. "Genes help wire up brains and guide individual neurons to
their destination," says Gary Marcus, a developmental psychologist at
New York University. "So genes play a pretty big role in building some
of our cognitive processes, like the kinds of memory and fundamental
reasoning skills we have."
In the absence of any other clues about a person's aptitudes, genetic
analysis, though imperfect, might be better than nothing. "Good
teachers try to tailor their teaching to an individual's strengths and
weaknesses," says Marcus. "The genome could be one more tool to guess
what these are." Genetic forecasting about talents or deficits that are
hard to assess early on in life could also prove useful. "Such
predictions might be useful if they are made in childhood. Parents can
make extra efforts, for example, to encourage the musical development
of a child with 'musicality' genes," says Judith Rich Harris, an
independent psychologist based in New Jersey.
This is already possible to some extent. "There are other ways of
finding out that one has untapped talents," Harris points out. As a
child she disliked and avoided maths, but in college she did
surprisingly well on a maths aptitude test, and even enjoyed taking
some maths classes. Later, when bedridden through illness, she worked
out a mathematical theory of human information processing that has
since been published. "Doing well on that test at the age of 20 made me
realise that my earlier avoidance of math had been a mistake," Harris
says.
Venter's biography offers a similar example. After enlisting in the US
navy, he, like all new recruits, went through a series of examinations,
including an IQ test. When the results came back, Venter found himself
top out of 35,000 test scores. This served as a wake-up call, making
him reconsider his academic potential, and setting him on the path to
his present position.
Clearly, life offers us many chances to test our aptitudes, and
information from a personal genome could be a useful complement. It
might even provide a basis for making ball-park predictions about how
children will turn out. As adults, though, we don't just want to know
about our strengths and weaknesses, we also want to understand how we
have become what we are. Where some people now look to psychotherapists
for such answers, in the future others may be tempted to consult their
DNA. Could the information packed into our genomes really change our
view of ourselves as individuals?
The answer might seem to be a resounding "yes". After all, geneticists
already compare the composite human and chimp genomes to get insights
into the genetic basis of chimp and human natures. So shouldn't a
comparison of genomic portraits from two individuals reveal the genetic
basis of why they differ?
What genes won't tell you
This is tricky terrain. The first misstep is to unreasonably elevate
the power of genes. "We measure the genetic effects because we can,"
Venter says. "We don't know how to measure all the environmental
effects that impact on our lives, or we would. The danger lies in
attributing too much significance to something just because you can
measure it."
A second and bigger stumbling block is that when thinking about
individuals, probability complicates matters enormously. "Probabilities
are perfectly reasonable as summaries of tendencies of multiple events
or individuals in a large sample," says Steven Pinker, a cognitive
psychologist at Harvard University, "but they are puzzling, perhaps
even meaningless, when applied to a single event or individual." The
relevance of probabilities after the event is even more questionable.
It is a moot point, for example, whether gene analysis could be used
objectively to determine the likelihood that a given pianist would have
become a pianist.
All this is an attempt to explain retrospectively why you are the way
you are. Though you can assign probabilities to candidate causes - to
this gene or that environmental effect - either, or both, could have
played a part in shaping you, with plenty of other factors and some
random noise thrown in for good measure.
Your long-lost twin
Nevertheless, there is a way of thinking about your genomic portrait
that might go some way towards helping you come to terms with who you
are. "Having one's genome decoded is like finding out that you have an
identical twin who was reared somewhere else," says Harris. "It lets
you see the possibilities your genes provided you with, the selves you
might have become, but didn't."
The "genomic twin" idea gives a visceral edge to thinking about the
cold, abstract strings of DNA code that spell out our genomes. Harris
tells a true story of twins separated at birth and raised apart. One
became a concert pianist, the other was offered music lessons in
childhood but declined. "I wonder what that twin thought when she met
her concert-pianist sister," she says. "Did she realise that she, too,
might have been an excellent musician if she had only accepted the
offer to take lessons?" These are ultimately unanswerable speculations,
but that doesn't diminish their intrigue for such curious animals as
humans.
Now imagine that you have had your genome decoded, and the sequence has
been sent to you on a CD. You pop it in your computer, run a scan and
find out that you have "musicality" genes (imagining for the moment
they exist and have been identified). How would you react? Well, such a
discovery should prompt the same kinds of reflections suggested by
Harris, with the same caveat. In both cases, we cannot unravel the
specific genetic, environmental and random effects that made us the way
we are - the probabilities make the picture so fuzzy you can't make out
details. In this case, the best you can do is to try your hand at piano
and see how it goes. Maybe you'll pick it up, maybe you won't.
In many cases, knowing that you have gene variants associated with
certain strengths or weaknesses, tastes or temperaments will probably
add little to your self-knowledge. "If I know that I'm impulsive, that
should affect how I evaluate an appealing temptation in front of me
now. If I know I have genes that probabilistically predispose me to
impulsiveness, that is far less relevant to my situation," Pinker
argues. "It's the impulsiveness that matters - whether it was
ultimately due to genes, environment, chance events in zigzagging
neurons is far less important, indeed, perhaps irrelevant."
What this boils down to is that if you are looking for self-knowledge,
genes are often not the best level of analysis. And that's not the
worst of it. "One of the biggest dangers of the information in the
genome is over-interpretation by society," says Venter. Genes at best
provide possibilities, not certainties. A particular suite of genes
might tend to be associated with high intelligence or a love of risks,
but they are no guarantee of such traits. The fact that we can talk
about such genes does not mean we should attribute too much power to
them. Another is the spectre of self-fulfilling prophecies. If you know
that you have genes typically associated with being bad at music, you
might convince yourself that you are just born without musicality. "If
people expect that they're not good at something, they tend to become
not good at that thing," says Marcus.
"If people expect to be not very good at something, they usually
aren't"
Looking into your genome could also dredge up trouble. Imagine that a
genome scan revealed that a law-abiding man had genes that gave him a
50 per cent chance of becoming a criminal. "Will he feel good that he
isn't in fact a criminal, or will the information itself make it more
likely that he will embark upon a new career as a law-breaker?" asks
Harris. "And what about the person with a similar genome who has
already committed a serious crime? Can we blame him and punish him for
his crime, if it was his genes that made him do it?"
With all this in mind, what do the experts conclude about the wisdom of
getting our genomes sequenced as soon as the technology makes it
feasible? Venter is optimistic about the promise of greater knowledge.
At the moment we face difficult questions about the underlying causes
for our unique repertoire of character traits. "When we have millions
of genomes in hand we'll begin to be able to answer these questions,"
says Venter. "Today we know almost nothing compared with what we'll
know in a decade or so."
Get one for your kids
Others are more circumspect, though there is general agreement that a
genomic portrait would provide useful medical forecasts and other
practical insights. Whether it would help you redefine your self-image
is more contentious. "For an adult, I don't think it would make much
difference. Whatever the genome brings us has already been considerably
shaped by the environment, enough so that you can learn a lot more
about a person by studying her directly than by studying her genome,"
says Marcus. "But new parents might some day want to purchase them to
get an early forecast of their children's likely aptitudes. After all,
even before we start to talk we've got a genome."
As the physicist Niels Bohr famously quipped: "Prediction is very
difficult, especially about the future." One thing is certain, though:
the more we study human genetic variation, the more we will know about
the genetic basis of our predispositions, predilections and potential,
so boosting our ability to predict how genes will affect the way people
turn out. Some of this progress will come through comparative studies
of the composite human genome and the genomes of chimps and other
primates. More will result from targeted studies into particular
diseases and conditions. And, if enough people follow Venter into the
realm of personal genomics and make their individual DNA available for
study, this will undoubtedly provide an additional and powerful lens
through which to look at nature and nurture, and how they modulate each
other.
The genome will never tell you everything, however. Even with a better
understanding of which genes are important and why, our genes will
never define our destiny. Venter is living proof of this. By many
measures he is a risk-taker - he is an avid sailor and has taken big
scientific chances in his career - but an analysis of his genome for
genes associated with risk-taking and thrill-seeking failed to turn up
the expected variants. That doesn't make him any less of a risk-taker.
It just means that his personality has developed that way regardless of
what his genes say.
>From issue 2565 of New Scientist magazine, 19 August 2006, page 28-36
To your good health
There has always been a discipline of "me-ology". It is called
diagnostic medicine. In the old days this was practised by waiting
until you felt unwell and then going to a doctor. Nowadays, there are
batteries of tests that can tell you things about your health long
before you notice any symptoms.
One is a full-body CT scan, a sophisticated X-ray that can pick up
early signs of cancer, heart disease, aneurysm, osteoporosis, kidney
stones, gallstones and more. It might even turn up a real surprise.
Perhaps you are a scientific curiosity - one of the 1 in 8500 people
who have a condition called situs inversus, in which your internal
organs are the wrong way round (heart on the right, liver on the left
and so on). The condition is almost entirely benign, so you might never
even know, unless you opt for that scan.
Other tests include DXA (dual energy X-ray absorptiometry), which
measures total body fat and bone density. A slew of blood, urine and
breath tests will tell you about such things as your cholesterol level
and organ functions, and pick up various diseases from diabetes and
gout to arthritis and cystitis. Some companies even sell home testing
kits that tell women their "ovarian reserve" - how many good-quality
eggs are left in their ovaries. Then there are genetic tests that will
increasingly be able to warn you in advance about the diseases that are
likely to strike you later in life (see main story).
The ultimate in medical crystal ball gazing, however, has to be a
scientific prediction of when you will die. To that end, Tom Perls of
Boston University has designed a questionnaire test based on the latest
gerontology (www.livingto100.com). Take it if you dare!
Graham Lawton
The way I see it
Most of us have more or less the same equipment that allows us to
touch, see, smell, taste and hear. Yet we all experience the world in
our own way. Your unique senses come from a combination of genetic,
physiological and psychological factors, many of which can be measured.
To gauge the strength of your taste response, for example, swab a
little blue food dye onto your tongue. The pink bumps you can see
standing out against the blue are your fungiform papillae, which house
your taste buds. Now take one of those small plastic rings used to
reinforce punched holes on paper, place it over the centre of your
tongue and count the bumps inside the hole. Researchers have used just
this measure to investigate our personal taste experiences. The average
number of bumps is around 20. Fifty or more, and you are a
"supertaster", experiencing certain tastes up to three times as
intensely as "non-tasters" - people with just five bumps. Add to this
your individual experiences of smell, mouth feel and consistency, and
you end up with your own personal flavour sensation.
Similarly, there is emerging evidence that we all live in our own world
of sound. A basic audiogram test will tell you whether you can hear in
the normal volume range: you press a button in response to a tone that
gets progressively quieter. Most people pass this test with flying
colours, but there is still a huge variation in our experience of
sound. Functional MRI tests reveal that different people have very
different patterns of brain activation in response to the same sounds.
As yet no one is sure why that is, but researchers at the UK's
Institute of Hearing Research are working on it.
As for sight, it seems that when it comes to the brain, we do have
similar experiences. A region involved in face recognition, for
example, lights up in response to a close-up shot, while the part used
for navigation is stimulated by landscapes. Still, there are individual
differences in the way we see the world. To test this try tuning a
television to the colours you think best represent real life, then ask
a roomful of people how they think it matches up. Chances are some will
find it too green, others too red and so on. Proof, if it were needed,
that your vision of reality is not the same as mine.
Caroline Williams
What is on your mind?
At around $1000 a pop, a personal brain scan is not the cheapest path
to self-knowledge, but it may give you some insights into hidden
aspects of your character and subconscious attitudes.
Perhaps you want to know how cool you are. Steve Quartz from the
California Institute of Technology in Pasadena reckons he can tell you.
He will record your brain's responses to a barrage of images of
products, brands and celebrities to gauge your emotional reactions to
what's hot and what's not. The results, he says, will tell you whether
you're a trendsetter or happy to follow the crowd.
Brain imaging can also reveal something about how the choices you make
are influenced by your emotions, gut instincts and subconscious. For
example, neuroeconomist Ernst Fehr from the University of Zurich in
Switzerland looked at fMRI scans of people while they were engaged in
tasks in which they had to cooperate and trust others to make financial
gains to assess how Machiavellian they were, and how much they enjoyed
punishing partners who cheat. Similar studies can reveal how gullible
or risk averse you are. Elizabeth Phelps of New York University has
even used brain scans to uncover subconscious prejudices in people
looking at faces of individuals of different races. Other studies show
that your brain's response to a moral dilemma can shed light on your
style of moral reasoning.
Is this really telling you anything new or that you couldn't find out
with a personality test or incisive conversation? Probably not. Yet
even if you already know that you are empathic, sensitive to the
suffering of others, impulsive or have a tendency to violence, it is
intriguing to see how your brain's responses in these contexts compare
with those of other people. But beware this line of thinking. In truth,
if you pay to have your brain scanned, the personality trait it is most
likely to reveal is egotism.
Helen Phillips
It is in your hands
If you have access to a photocopier, this couldn't be simpler. Take a
picture of your right hand, palm down. Now measure the lengths of your
index and ring fingers, starting at the crease nearest your palm. Then
divide the former by the latter to give your very own "second to fourth
digit ratio" or 2D:4D. Not impressed? Well you should be, because this
little number says a lot about you - from your sexuality and
personality to athletic prowess and the diseases you are likely to get.
Your 2D:4D seems to be a measure of the levels of sex hormones you were
exposed to when you were in your mother's womb, explains John Manning,
a pioneer in this field from the University of Central Lancashire, UK.
The more testosterone, the longer your ring finger will be; the more
oestrogen, the longer the index finger. Women tend to have a 2D:4D
close to 1, while men are usually lower at around 0.96. How much you
differ from the average is an indicator of how feminised or
masculinised you are.
Studies show that traditional "male" qualities such as assertiveness
and skill at certain mathematical tasks such as rotations are more
likely to be found in both men and women with a low 2D:4D. Low-ratio
men have more sexual partners and more children than high-ratio men,
while the most fertile women are those with high 2D:4D. High-ratio
people of both sexes are most likely to be neurotic. Controversially,
gay men seem to have relatively high 2D:4D and lesbians have a low
ratio. Your ratio can even predict your susceptibility to certain
diseases: women with higher ratios seem to be more susceptible to
breast and cervical cancer, while high-ratio men tend towards heart
disease.
On a more positive note, anyone with a low 2D:4D is likely to have
higher than average aerobic efficiency, which means you should be good
at endurance sports. So, if you are deciding whether or not to sign up
for the next marathon, head for the photocopier.
Kate Douglas
Bright future
"How smart are you?" "What kind of intelligence do you have?" "Test
your emotional intelligence". A quick Google of such phrases will bring
up enough intelligence tests to keep you occupied for weeks. When you
get bored, you can even test your dog. Online tests can be fun, but you
shouldn't take the results too seriously. The validity of tests
claiming to measure emotional intelligence is questioned by many
psychologists, for instance, as is the whole notion that there are
different kinds of intelligence.
For an accurate measure of your IQ, you will need to do a formal test
such as the Wechsler Adult Intelligence Scale III, which has to be
given by a trained tester. This measures different aspects of
intelligence, such as verbal comprehension, processing speed and
working memory, but people's scores in each aspect are closely related,
which is why the test is said to measure general intelligence, or g.
Although the use of such tests is highly controversial, there is no
doubt the results are a good predictor of how well people will perform
academically and in their jobs. What's more, as a New Scientist reader,
you can be confident of your result - you are damn smart.
Michael Le Page
Where do I come from?
Ever wondered if your parents brought the wrong baby home from the
hospital? Or perhaps you think you might be descended from Joan of Arc
or the Irish King Niall of the Nine Hostages? A host of companies now
offer genetic genealogy tests. These can tell you whether you share a
recent common ancestor with another individual, whether your family
tree is correct, where in the world your ancestors came from and even
from which ancient human lineage you descend.
The results of such tests need to be treated with caution, however.
Most look either at the Y chromosome, which is passed from father to
son, or at mitochondrial DNA, inherited from your mother. Such tests
tell you nothing about your father's mother, or your mother's father,
and so on. Go back 14 generations and you have 16,384 ancestors, but
only one provided your Y chromosome (if you have one) and only one
donated your mitochondrial DNA.
What's more, the accuracy of such tests depends on how many distinct
variations, or markers, they look at. An accounting professor in
Florida recently hit the headlines when he was told he was a direct
descendant of Genghis Khan. As many as 16 million men living in a broad
swathe across Asia share the same Y chromosome, thought to be that of
the Mongol conqueror. The professor's result was baffling, though,
because he is of European descent. The mystery was solved when a second
test looking at more markers ruled out any relation to marauding
Mongols.
Tracing geographical ancestry can also be difficult. It is only
possible, for instance, to say that you are from a specific tribe in
west Africa if you have a pattern of markers unique to that tribe. Yet
most mitochondrial DNA patterns are found in all populations across
west Africa, making such tests a disappointment to many African
Americans hoping to trace their roots. A newer method called
biogeographical ancestry estimation can provide a more comprehensive
picture. It looks at 200 or so markers on several different
chromosomes. The result might tell you, for instance, that you are 75
per cent western European and 25 per cent Native American.
One thing is for sure: as sequencing methods improve and databases
expand, genetic testing will get cheaper and better, and reveal ever
more about our ancestry.
Michael Le Page
Up close and personal
Few things are more personal than personality, and if you are curious
about yours, there is no shortage of ways to find out. Just don't
expect anything too subtle. A questionnnaire to "reveal" whether you
are an introvert or an extrovert, for instance, might ask: "if you meet
a group of new people, do you (a) stick with your friends, or (b)
mingle as much as possible?". Yet tests similar to these are the staple
diet of personality research, and they can reveal a surprising amount
about your biological make-up.
The idea that people can be classified into personality types is as old
as civilisation itself. The 2nd-century Greek physician Galen thought
that personality was constructed from four basic elements: melancholia,
irritability, optimism and phlegmatism. Modern theories take a similar
approach, but generally break it down into the five "dimensions"
extroversion, neuroticism, agreeableness, conscientiousness and
openness to experience. Your score on each dimension, as measured by a
detailed questionnaire, determines your overall personality.
Over the past decade, personality research has been invaded by
geneticists, molecular biologists and neuroscientists, all searching
for the "biological correlates of personality" - actual physical
differences between individuals that can explain the variation in their
personality scores. As a result the field has become much more grounded
in hard biology. Twin studies, for example, suggest that your genes
have at least as much influence on your personality as your upbringing
and experiences. The genes themselves are also coming into focus, with
dozens of gene variants now linked with various personality traits.
Meanwhile, neuroscientists have discovered that there are real,
consistent differences in brain activity between people who score high
or low on certain personality traits. Personality testing may once have
been dismissed as mere psychobabble, but it is rapidly becoming an
objective science of me.
Graham Lawton