Knowledge of our genetic code has radically altered our understanding of our lives.

Just as there was a 19th-century Darwinian revolution which transformed how humans viewed themselves and their place in the world, the late 20th century has seen a revolution changing our perceptions of who we are, where we came from and how we relate to other humans and to other species on our planet.

Genes and genetics have been widely taken up in western public discourse as explanatory and inspirational symbols, but the science of genetics moves exceptionally fast, not just in terms of technical details but also in the far-reaching social and medical implications of what is revealed. It is essential that scientists are able to communicate new developments accurately and clearly, which has not always been the case. Media focus on the negative aspects of genetic discoveries results in scare stories about 'designer babies' and cloning. Failure to highlight the time lag between the discovery of a disease-related gene and the development of tests and treatment for the disease can raise false hopes in sufferers from that disease or their families.

The increasing dominance of genetics in public discourse in the last decade could result in a shift towards us viewing ourselves in a way that is completely genetic, a tendency to look to our genes to explain everything about who we are. The debate over what our children inherit from us, and what impact environment and conditioning have on them - which used to be known as the nature versus nurture debate - is now understood in terms of DNA. But it is the complex interactions that take place between our DNA and the environment that make us who we are, not solely our genes.

Discoveries in the field of genetics have not just had a profound impact on our perception of ourselves, but on our conceptualizations of human difference and how we relate to other human beings. The role of race in human genetics is hugely controversial but it is clear that what is called 'race', although culturally important, reflects just a few continuous traits determined by a fraction of our genes. From the perspective of genes, it is the case that the great majority of genetic variation is between individuals rather than races. Two people from the same region who look superficially alike can be less related to each other than they are to people from other parts of the world who may look very different.

Genetic research has also appeared to blur and shrink the difference between humans and other mammals. We are frequently reminded that we share between 94 and 98 per cent of our genes with our closest living ancestors, chimpanzees. Although this reinforces Darwin's theory about our close relationship to the apes, which shocked Victorian society, it also usefully illustrates the complexity of our genetic programming and how small variations - in this case between 6 and 2 per cent - can make literally a world of difference. Comparing chimp and human genomes can also shed light on the past six million years or so of evolution, since the two species diverged from an apelike common ancestor.

The mapping of the human genome could have re-fashioned our perceptions of ourselves in a rather sterile and utilitarian way, reducing us to chemical assemblages that temporarily stabilise DNA for the duration of the human life span. This would make humans merely the sum of our genes, a development that has been referred to as 'geneticisation'. In fact, advances in genetics understanding have served to underline the immense complexity and wonder of the human being. Scientists struggling to explain to the public the extraordinary discoveries they are making in scientific language are forced to use metaphors and analogies, sometimes almost poetic, to convey their complexity and scale. Thus Francis Collins, the leader of the US Human Genome Project, described the results of the project as "the first draft of the human book of life…the first glimpse of our own instruction book".