Human genome: Nature or nurture?

The human genome project has revealed that our genetic make-up is far less complicated than first thought.

Researchers have worked out that as few as 30,000 genes are needed to produce a human, only twice as many as the humble fruitfly.

One of the scientists behind the project, Dr Craig Venter says this would suggest our behaviour is not determined by our genes, with environmental factors playing a large part in shaping our thoughts and actions.

To what extent are we products of our genes? Or does the world around us shape our behaviour? Are we creations of nature or nurture?

This debate is now closed. Read a selection of your comments below.

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Your reaction

The question about the influence of nature and nurture is all very interesting, but why don't we ask the proper questions like who are the people, even now, ahead of any legislation who are secretly cloning individuals of particular qualities, gifts and persuasions? We cannot really afford to get sidetracked by any 'romantic' ideas. Man now has the ultimate weapon against humanity in being able to create individuals to order with all the qualities possible and to tinker with life itself.
Jim Bogusz, UK

Twentieth century science developed the bad habit of implying that we have understood more than we really have

Jonathan Kerr, UK

The new knowledge about our genetic make-up is very interesting, and will almost certainly be very useful in the future. It is also interesting to try to disentangle the influences of nature and nurture, though at present the genetic knowledge doesn't help much with this, it is still best done by studying individuals, such as identical twins.

But philosophically the same mysteries remain, and if we are to tackle them this century, we must surely face the fact that they're there. Twentieth century science developed the bad habit of implying that we have understood more than we really have. The philosophical questions about the nature of life, and particularly humans, are unaltered by the progress in genetics, though some people are now implying that we now know it all. I suppose it makes them feel more secure, but good science is about facing up to what we don't know, and then tackling it.
Jonathan Kerr, UK

I do partially agree with Dr Craig Venter that our behaviour is not determined (entirely) by our genes, but with environmental factors playing a major role in shaping our thoughts and actions, but isn't it our genes that give us the ability to behave in such a manner to our environment? Isn't it not the genes that make a human a human and a fruit fly what it is? Isn't it that mutations in genes caused modifications in individuals of a species that allowed some to flourish and some to perish in the given environment - the whole theory of natural selection?
RBD, India

People happily accept that puppies from the same litter can develop completely different personalities whilst they are still with their mother yet won't believe that human beings are also greatly influenced by nature. They will be saying next that a persons sex is wholly determined by the way that they are raised and all we have to do to turn a boy baby female is dress him in pink and give him dolls to play with.
Gill, UK

A combination of both Nature and Nurture makes us who we are as individuals. Take the example of speaking a language. Speaking English or German or Chinese is not genetically controlled. We were not born speaking a specific language but learned the one that our parents taught us. However, I would not be surprised if our ability to learn languages was genetically controlled. For example, some people have better aptitudes to learn several foreign languages than others, and this may in part (of course not only) be genetically controlled. Also, on a different scale, gorillas can be taught sign languages and can use a limited number of words. However, they will never be able to have discussions at the level that we do as humans, simply because they do not have the same genes and abilities. Genes and what we do with them are both important!
Sylvestre, France

Our understanding of how life truly works really is in its infancy

Seth Kendall, UK

I have to say that I am somewhat sceptical about this recent news story. Just because human beings only have 30,000 genes does not necessarily mean that nurture plays a bigger role than we previously thought. This might be the correct explanation, but our reaction of surprise should not really be given too much weight. Remember, we only discovered DNA 50 years ago. Our understanding of how life truly works really is in its infancy and I think reactions of surprise will occur regularly as we begin to unravel the last 3500 million years.
Seth Kendall, UK

The fact that we have only double the amount of genes of a fruit fly says nothing about the nature/nurture argument. If it did demonstrate anything about the nature/nurture argument, then surely, it should be possible to nurture a fruit fly to a rudimentary understanding of mathematics (say half of what we know), to learn a 13 letter alphabet etc. etc. It is a flawed assumption to say that, because we have only twice as many genes, that we are at all similar. The added complexity that can be represented by a further 15,000 or so genes is a factor larger than most people could possibly imagine. It does not represent a complexity increase of two, but of many many millions. Plenty of room for nature to store many of the traits that make us human...
Chris, UK

Whist the culmination of the genome project is good, there is too much hype, like usual. All we have done at the moment is to measure, just because we can count and name something does not mean we will ever be able to use or understand this vast amount of information for a very long time. It is like being asked to describe a book and then measuring its height, length, depth and then counting how many letters and words are in it. In my opinion we have a long way to go.
E, UK

As an identical twin myself, I and my brother are only too well aware of the sameness and difference in our make-up as persons. Each person's potential is largely determined by his or her genes. Education and other learning experiences forge that, but the final agent determining the realisation of one's potential is your own human will and courage.
Trevor H, England

Even if we can replicate a human being - we cannot replicate the way its original grew or the emotions involved that made it a mature individual or the surroundings that helped in developing skills to live in society as a productive citizen. The technology discovered can no doubt prove useful in the medical arena - but so far as creation is involved, you can't beat Nature - the brilliance of creation is something you cannot comprehend, even if you create a new biological specimen, it will be interesting to watch how it will survive in nature and not man-made nature.
Sean D'Souza, USA

We have inherent capabilities, interests and leanings

Rebecca Southwell, UK

To my mind, Dr Robert Winston successfully highlighted the importance of nature in moulding the "personalities" we become in a ground-breaking documentary about identical twins. Tests showed that identical twins separated at birth and put into two completely opposing environments would follow a similar course. Interestingly, one sample set shared a mutual love of reading. Whilst one had access to a vast personal collection, the other twin was in an extremely poor family but instead joined a local library. Illustrating that we have inherent capabilities, interests and leanings. Of course there is always the exception but Dr Winston also managed to correlate a relationship between crime and the gene make-up.
Rebecca Southwell, UK

Sounds like nature gives us a predisposition for something and nurturing encourages or discourages that behaviour.
Gerry, Scotland

It is exactly because all sorts of environmental factors contribute to who we are as individuals - from how well the embryo is nourished in the womb to the sort of education we get - which is why cloning of human beings would be pointless; you'd get a physically similar but a totally different individual by experience every time. Of course, clones would all learn to walk and talk etc. as controlled by their genes, but even how well they did those things would differ from the "original" individual. It must be the case that our genes determine how our life experiences will shape us, because we are nothing without experience - or a repository for that experience to act upon.
Steve, UK

I think we are more dictated to by our genes than we would like to think. Genes can determine what type of chemical receptor we have in the brain, and the levels of the brain chemicals. These, in turn, can control (to a limited extent - it's not absolute!) whether or not we are thrill-seekers, whether or not we are phlegmatic, and whether or not we are fastidious in our personalities. These are factors, which I'm sure, many people believe - and want to believe - that we, as freethinking individuals, are in total control of. Well, we're not. And to those who claim that chimp behaviour is completely different to ours - and therefore the nurture must predominate, lets look at our more basic instincts, our bigotry towards immigrants and anyone who is different. Chimps will attack and kill a chimp from a different area. We haven't evolved that far, have we?
Francis Fluka, UK

One scientific point seems to have been totally ignored again. One gene is not solely responsible for one trait. It is the inter-relationship of several genes that creates an observed trait. Different species may have the same genes, but they use them in combination to differing extents. Complexity therefore comes from different interactions between genes, not from the number of genes.
Paul, UK

I think both genes and environment help shape the person. Environmental factors are demonstrated by inter-generational welfare dependency, and academic achievers who grow up surrounded by books and encouragement from parents. Genetic factors have been evidenced by adoptees, taken in to nurturing families, with behavioural problems emerging in later stages of development. As most scientists tell us, there is nothing particularly remarkable about life, so let them get on with the job of perfecting it.
Tom, Australia

To my understanding, the one critical factor that sets us apart from other species is our ability to make choices. Many of these choices may be made at a subconscious level and are influenced by socio-economics, upbringing, peer groups, climate etc. which would explain why humans are so good at adapting. Natural selection may have granted us large brains, but has nothing to do with the way we use them, that's down to us and our self-imposed values.
Peter Whiskin, UK

We look at the night sky and see approximately the same number of stars but is universe that simple?

Dmitry S., Russia

As few as 30,000 ... Isn't it quite a lot and only a minuscule portion of it is understood? In comparison to a fruit fly all it says is that a fly is not a primitive creature but an advanced organism perfectly adapted to its environment. And do we understand 15000 genes of the fruit fly? With all our sophistication, supercomputers and everything we cannot build even simplest bacteria or virus - it's too complex for us.
We still don't have cure for AIDS after 20 years. We look at the night sky and see approximately the same number of stars but is universe that simple? What it hopefully says is that possibilities of science are limitless and we better devote our resources to understanding and improving ourselves than to viewing each other with suspicion over religious, economical and military barriers. Human Genome project is better than Star Wars.
Dmitry S., Russia

I guess history and even simple intuition had explained to us that a human put in space alone is just a human body. It is this interaction with environment that prevents our brains from being atrophied. It is this vast information that we get from environment through our vision, hearing, touch, and even our hearts that make our existence meaningful. We are different from most nature creatures by the ability to benefit from the continuous surrounding input to develop into the better regardless of the number of our genes.
F J, USA

If our ancestors were able to give themselves an advantage by nurturing some skill (like language) then those of them who responded best to the nurture would have the best advantage. Thus genes that made our ancestors respond more effectively to the nurturing of language would be successful genes. As soon as our ancestors started nurturing for advantage, evolutionary pressure favoured genes that aided the nurturing process. So the two are inextricably linked. It is impossible (sadly) to nurture beyond that which nature makes possible - try teaching your cat the play the piano. Nurture brings out what nature allows, which varies from one individual (or species) to another. This fact may be unpleasant but we must accept it and be sure that no one build some perverse ethical framework on this basis. We are born unequal and our mission should be to equalise nature's unfairness with extra nurture where it is most needed.
RM, UK

Having a limited number of coherent genes doesn't mean our genome isn't complex

Hesham, New Zealand

I've previously thought that human genome would be very complex when compared to other species/creatures. However, having a limited number of coherent genes doesn't mean our genome isn't complex. Firstly, a small number of genes can do a major difference in structure and behaviour as has been previously mentioned in this column. Secondly, let's not underestimate the potentials of introns, those "redundant" sequences of base pairs in DNA that interrupt the continuity of genes. I would be particularly interested in finding out the trend and the complexity of introns in humans as compared to other species.
Hesham, New Zealand

Maybe the scientists should now try to seek and answer as to why a pair of twins end up having different personalities right from birth onwards?
Guru Shenoy, United States

Our genes certainly do not determine who we are! I believe that the environment we are raised in determines the outlooks and attitudes we will have in life. This fact is supported by various empirical research like that of twins raised in differing environments and as a result behaving as different individuals. I also have faith in the fact that people can look beyond the chemistry of life and focus on what truly makes us humans, our souls.
Sil, Canada

Northwestern University did a definitive study on identical twins (mono-zygotic) who were reared apart. They gave them IQ; psychological; personality; and every other test you can think of. They know, with great certainty, what we are born with and what we develop. There is not much doubt exactly how much is nature/nurture. I do feel that they "toned down" the results for political correctness though.
Colin Butts, USA

There is no gene for the human spirit
Craig, Australia

Genes are not producing a human, but a human body

Christian Bodhi, UK

"30,000 genes are needed to produce a human" This is an incorrect statement. First, genes are not producing a human, but a human body. Second, genes are only molecules that have no will of their own to produce anything. Therefore the question is who or what is 'producing' a man. Famous physicist David Bohm who was a colleague of Einstein postulated that present forms including life forms are enfoldment of implicit order which is contained in the forces of nature itself. Hence man is a manifestation of that order or as philosophers would say the Universe observes itself through the self-conscious man.
Christian Bodhi, UK

Whereas once, nature in its purest sense was responsible for our 'behaviour', i.e. from the first replicating molecules, we have now shifted the balance (and human evolution) very much into the 'nurture'/ 'nature by design' domain. Perhaps this is the only result available to billions of years of natural selection?
Mark Inno, Austria

It doesn't really matter whether our genes make us 100% what we are. All I hope is now, the scientists and doctors can use the genetic code to find a long awaited cure for genetic diseases such as Epidermolysis Bullosa.
Paul, Wales, UK

It should be noted that experience also plays a part in determining synaptic connectivity and activity in the brain and also possibly plays a role in determining synaptic connectivity in the periphery eg motor neurones. Our genes do have a great effect in determining our physical characteristics but so does experience and at more than a psycological level.
Chris, UK

What is frightening is that the human race now controls not just nurture, but nature as well

P, US

It seems to me that we are first and foremost what our genes decide we are. When more is known I would not even be surprised if it is our genes that strongly influence how we respond to major issues of survival. Our nurture comes in to play, and so also has a significant impact on us, in influencing how we interpret the situations to which we then respond. The questions was "are we creations of nature or nurture." What is frightening is that the human race now controls not just nurture, but nature as well. Is there anything in all of human history that indicates this is a good idea? Yes, treating horrible diseases with "genetic surgery" sounds wonderful. Is there anything in human history that suggests this will be its major use?
P, US

This is a good discovery as far as the scientists are concerned. But, this is bad as far as the human race is concerned. Less genes = more easy to edit. Scientists will find it easier to make designer babies with less genes, once they start fiddling and finding out just what the genes do. Today is a dark day for humanity.
Paul Tomlinson, Great Britain

I see our behaviour as controlled by both our genes and our environment. Our genes determine the shape of our brains (the 'hardware' of thought) and our environment overlays this (the 'software'). Interestingly, since we have no control over the genes we inherit or the environment we are brought up in, we can have no free will. Even if I now decide to change my environment, that thought will be the result of my genes and my current environment.
Ian, UK

It is not where you are from it is where you are at. Everybody is born with the potential to do what ever they want, But only those who make the effort succeed.
Ateeq Mogal, Saudi Arabia

There is only a 2% difference between human beings and chimpanzees, yet behaviouraly there is an enormous gulf

J Hadlee, UK

There is only a 2% difference between human beings and chimpanzees, yet behaviouraly there is an enormous gulf. This would seem to suggest that a very small variation in genes can have create a vast difference in behaviour. The discovery that we have fewer genes than we thought adds to the nature/nurture debate, but it proves nothing other than that a few genes go a long way.
J Hadlee, UK

We're the product of both. Our genes give us certain potentials and characteristics, but whether these are realised and how they manifest is to an extent determined by our upbringing and social context. The nature/nurture debate is a nonsense in the sense that it follows an 'either/or' logic. Both nature AND nurture matter and inform and influence each other.
Khan, UK

Obviously, simply by the way genes work, we are products of them in the physical sense. But character seems far more to do with nurture than any inherent nature. The fact general character can change has been shown in numerous occasions eg rehabilitated criminals, religious converts are people who have undergone basic character changes. in my humble view. Perhaps it always be argued that genes are chemically responsible for emotional characteristics, like they are for physical ones. But it seems nurture lays the boundaries on how far these emotional characteristics develop.
Z Shah, UK

Don`t you think that the greater you know about the human race the more confused you will be? Better think of the issue as the business of God?
Jimmy Gamal, Egypt

Why do you insist on posing the question in either/or terms? Just to stir up controversy, evidently. It is clear that a combination of both nature (genetic endowment) and nurture (environmental influences) determines behaviour. Sorting these influences out (to the extent possible) is the issue, not "either/or".
R.B.Norman, U.S.A.

Nature and nurture are both vital ingredients for a fulfilling human life. Nature without nurture can certainly be dangerous!
Priyangi, UK

Yes it would seem that a few genes go a long way, but also maybe we have too many. Who is more perfectly adapted to their environment? Us? Or the humble fruit fly? Maybe evolution will allow us to lose a few thousand genes and become a better species?
Simon, England

In terms of evolutionary origins, we are creatures of nature (which itself created the genes). In terms of specific dominant behavior, we are creatures of nurture

Robert Farrell, USA

In terms of evolutionary origins, we are creatures of nature (which itself created the genes). In terms of specific dominant behavior, we are creatures of nurture. That is to say: The original effect of genetic identity - a completely "natural"occurrence - has gradually become the cause of further development. The crucial question then has become what is man? Since this quality of nurture has risen to predominance. The answer appears to be man is his own domain. Not fighting nature, but certainly superseding it.
Robert Farrell, USA

Nature or nurture? How illogical! This is a very good example of a hidden assumption. It assumes that those are the only two factors in man's behaviour when in fact there is a far more important third factor. That factor is the human soul. The entire argument is therefore skewed, since it is rather like your readers trying to determine who and what I am by taking apart their PCs and examining their browser software while forgetting that there is a human being at the other end of the line.
David Szondy, USA (British)

The 'either/or' question is a useful one to promote discussion but clearly the answer has to be both. Try this test. A baby is born and is kept in complete isolation from its fellow humans for all of its life. Nutrition would be provided remotely. The question is, would that being be considered human? Obviously, the answer is yes because it would have all of the physical characteristics of a human. Would it be considered to be 'normal' in any sort of generally accepted way? Answer is no, because of its social deprivation. Hence, I support the earlier 'hardware' and 'software' analogy of human development quoted by Ian, UK
Roger, England

Obviously, it's a combination of both nature and nurture. But of more interest, perhaps, is how the human brain will evolve over the forthcoming thousands of years (assuming we survive as a species). Will we become more "brainy" and less physical? Will we develop new skills, like ESP? When we go into space, what will that do to our psychology? And does our evolution so far give us any clues to this future? These are fascinating questions, though I'm not sure there are too many answers!
Mark M Newdick, USA/UK

There are several limitations to the power of genes , it seems to me. First , the genome is only the initial plan. It has to be interpreted by the female matrix. Some fluctuations and deviations may occur at that point. Also, it is possible that the development of a human being might be considered like the evolution of a mathematical sequence, each term depending on the preceding one to be evaluated. The first term would be the initial genome and the chemical state of the matrix, which would lead to the second state after some development time, and so on. Under those terms, tiny differences in the beginning can produce an enormous amount of combinations in the end, possibly so enormous that it cannot be evaluated in a reasonable amount of time, even with powerful (quantum ?) computers. So editing may not be so easy , even with 'only' 30000 genes. Furthermore, some argue that the deep operation of the brain might be based on quantum phenomena. If that is the case, there is a fundamental uncertainty at work, that is part of the very fabric of the universe, and genes have little power over it. To sum up, there is uncertainty in the way the hardware is built, uncertainty in the way it operates, and extremely fuzzy and unpredictable 'programming practices' for the software, so we are far from a clear-cut determinism.
Olivier Houot, France