Cancer, diabetes, dementia and cystic fibrosis: having the genome has not meant an end to these afflictions

OPINION:IT WAS ALWAYS on the cards that scientists would attempt to decipher the human genetic blueprint once its disarmingly simple structure and component parts were revealed. And, once discoverers Watson and Crick had identified the structure, it immediately became apparent how DNA manages to copy itself with such a startling degree of accuracy.

When a concerted effort to map human DNA got under way in 1990 under the Human Genome Project, the assumption was that once we knew the step-by-step details of the blueprint all would be revealed. We would develop a new understanding of genes and how they worked, and also of disease. We already knew we could engineer DNA, so it was not a fantastical leap to assume we would finally gain power over disease and ageing.

It took $1 billion (€738 million) and a collaborative effort by scientists around the world, but a decade later it was delivered. We had mapped a human and defined a species.

Ten years on from that momentous achievement, we still struggle with cancer, diabetes, dementia and cystic fibrosis. Having the genome has not meant an end to these afflictions.

That is not to say that no progress has been made. Earlier this month, Science journal celebrated the tenth anniversary of the accomplishment with a series of essays. Players in the race to deliver the genome – along with theologians, clinicians, evolutionary scientists and artists – were asked to comment on where we stand 10 years on.

Although their progress is slow, the progression of disease is being picked apart by scientists who use the genome to understand changes from the norm that are triggered by the onset of disease. Scrutiny of a patient’s DNA has yielded successes, for example helping to treat a six-year-old suffering from inflammatory bowel disease, says Francis Collins, director of the US National Institutes of Health and a leader in the genome project. The genetic discovery can be duplicated in others and there are more such examples every day he says.

The limitations of the approach are highlighted by another key player in the genome project, Craig Venter, who heads the J Craig Venter Institute in California. He antagonised many scientists by pursuing his own DNA sequencing approach, suggesting he would retain control over the knowledge rather than release it to the world. In the end he joined with the world consortium to release the genome.

While having the genome opens the way to better treatments and personalised medicine, it has also opened the door to fraudulent practitioners who sell dubious treatments of little value. This, Collins writes, “has made deceptive marketing a reality in some instances.

“We have come a long way in genomics; however, for genome sequencing to reach its full potential, we still have a long way to go.”

Defining the genome has also brought into question what it means to be human, according to a professor of theology and ethics at the Pittsburgh Theological Seminary, Ronald Cole-Turner. It quickly became apparent to scientists that all species – plants, animals and humans – are built from the same genetic stuff, the same small collection of chemicals ordered in varying ways.

“The ‘human’ genome, it turns out, consists of sequences that are widely shared across the evolutionary tree,” he writes. Comparing the human and chimpanzee genomes quickly showed our human uniqueness “is thin indeed”, he adds. “The Human Genome Project undermines cherished ideas about human uniqueness. But it also hints at a new vision of humanity.”

It is through these very comparisons between species that evolutionary geneticists can demonstrate our connectedness with the rest of life on this planet. It traces our relatedness within our own species but also to much older ancestors, says Molly Przeworski, a professor at the University of Chicago. “For population genetics, this ushers in a previously unimaginable opportunity to reconstruct the entire genealogical and mutational history of humans,” she says.

And yet those involved in the field constantly return to the biological basics, how a better understanding of the genome and how it works should lead to advances in medical treatments. Tom Hudson, the president of the Ontario Institute for Cancer Research in Toronto, acknowledges that no one could have predicted the million-fold increase in genomic information over the past decade.

However, he also says that, had more been invested in accumulating detailed clinical histories of patients coming under genetic scrutiny, then more progress in treatments could have been made.

“If genomics were now being integrated with such resources, we would be closer to achieving a form of personalised medicine that clinicians would be eager to adopt.”