Does our DNA define us?
All of us begin our lives as a single-celled embryo. The DNA in this embryo – our genome, composed of DNA inherited from our parents – is replicated throughout most of the cells of our adult body. Yet the question of the degree to which this DNA affects our behaviour, our aptitudes and our appetites throughout the remainder of our lives has proved contentious and volatile for well over a century.
In his new book, Blueprint: How DNA Makes Us Who We Are, Robert Plomin – the world’s leading behavioural geneticist – draws upon his 40 years of research, his 800 scientific papers and his longstanding involvement in public and policy debate to argue that our inherited DNA differences are the major systematic force that makes us who we are as individuals. This conclusion is certainly controversial, seemingly at odds with the importance ascribed to our education, and the environment in which we grow up, in shaping the person we become.
What has led to, and what are the implications of, Professor Plomin’s conclusion? Is there any scope – within the natural sciences, and more generally – to dissent from it? Can we make confident assertions about the genetic determination of human thought and behaviour, without thereby promoting genetic determinism? If we start making predictions about people’s lives and potential on the basis of their DNA, does this risk reducing their autonomy and foreclosing their futures, or could it open up new ways to help them and maximise their opportunities?
There is already a burgeoning international market in direct-to-consumer genetic testing services, like 23andMe, which governments struggle to regulate. Should we dissuade people from seeking out such tests and ascribing importance to them, or – now that this ‘gene genie’ is out of the bottle – should we be thinking instead about how to improve upon and standardise genetic tests, promoting better understanding and use of them? In future, will we routinely sequence the whole genomes of babies at, or even before, their birth? What can our DNA tell us, and what can’t our DNA tell us, about what and who we are?