In absorbing new popular science title The Genome Odyssey, Stanford University Professor of Medicine and Genetics Dr Euan Angus Ashley reveals how our understanding of the human genome is revolutionizing medicine, finally unlocking the answers to mystery illnesses and leading to exciting new treatments for many of today’s most devastating diseases.

By Timothy Arden

In 2003, an international project to sequence the entire human genome—all the genetic instructions found within the human body—was finally completed. 

It had taken a decade of research, and had cost several billion dollars to realise, but the effort was rightly recognised as one of the greatest scientific achievements in history, on a par with the first Moon landing. 

It was nothing short of a giant leap in our understanding of genetics and came with the expectation that this knowledge could one day be used to treat or even prevent thousands of diseases—from the most common killers to the rarest conditions, affecting only a handful of people across the planet.  

As The Genome Odyssey: Medical Mysteries and the Incredible Quest to Solve Them reveals, that early promise is now fast becoming reality, opening up a bold, exciting new era of genomic-based medicine that will totally transform society and our quality of life. 

And who better to provide a guided tour to this unfolding medical revolution than one of the world’s leading experts on genetic-based medicine: Dr Euan Ashley. 

Dr Ashley, who was born in Scotland but who is now based in the United States, is recognised as a pioneer in the application of gene sequencing in medicine and is right at the forefront of the field, being Professor of Medicine and Genetics at Stanford University, the Head of Stanford Center for Undiagnosed Diseases, and the founding director of the Center for Inherited Cardiovascular Disease as well as Stanford’s Clinical Genomics Program. 

He joined Stanford to train as a cardiologist in 2006, after completing a Ph.D. at Oxford University in cardiovascular biology, and has witnessed first-hand how rapidly genomic medicine has become integrated into healthcare.  

Early on in the book, which has just been published through St. Martin’s Press, Dr Ashley observes through analogy that the growth of the sector has all been made possible thanks to the huge drop in the cost of sequencing an individual’s DNA. He writes… 

“My commute, at the time, took me past the Ferrari-Maserati dealership near Atherton—billionaire territory in the heart of Silicon Valley. I would often cast a sideways glance at those cars as I waited in traffic. One day, I was sitting at the stoplight doing random math in my head, as one does, and realized that if the Ferrari in the window had dropped in price as much as human sequencing had dropped in price in the eight years since the Human Genome Project’s draft sequence was released, instead of $350,000 it would cost less than forty cents. A forty-cent Ferrari! A millionfold reduction in price.” 

He goes on to say that this incredible reduction in cost has “fuelled a tsunami of scientific discovery” which has “given the medical profession an unparalleled opportunity to change lives for the better”. 

Dr Euan Angus Ashley is Professor of Medicine and Genetics at Stanford University and a pioneer in the application of gene sequencing in medicine.Dr Euan Angus Ashley is Professor of Medicine and Genetics at Stanford University and a pioneer in the application of gene sequencing in medicine.
Dr Euan Angus Ashley is Professor of Medicine and Genetics at Stanford University and a pioneer in the application of gene sequencing in medicine.

The Genome Odyssey underlines just how dramatic that change has been, bringing newfound hope to people around the world.  

Running to around 400 pages in length, the book is divided into four sections with the first, ‘The Early Genomes’, introducing the reader to the medical team that Dr Ashley leads and providing an account of their first steps into genomic-based diagnosis. 

In another’s hands the subject could easily have become complex, dry, and off-putting but Dr Ashley wisely makes the patient the focus from the get-go , presenting the personal stories of those who have benefitted from this new era of medical treatments to illustrate clearly how genomic medicine is actually making a profound difference to people’s lives.  

Take, for instance, Parker—a young boy who had seemingly been a healthy baby upon delivery but who, as the weeks and months progressed, began to show clear and worrying signs of developmental delay.  

By the time his parents met with Dr Ashley and his team five years later they had gone from pillar to post to try to find out what was wrong with their son, who was also now suffering alarming seizures. Despite numerous and often painful tests, all the medical professionals had drawn a complete blank. 

Dr Ashley’s team sequenced Parker’s DNA from a blood sample and from this were finally able to give his parents the answers they had desperately been seeking. It turned out that he had a new type of genetic mutation disrupting a gene called FOXG1.  

With this diagnosis, which would never have been possible before the Human Genome Project, Parker’s parents could tap into a small yet international support network of families suffering from FOXG1 syndrome and, more importantly, have his medication modified, resulting in their child’s symptoms being dramatically reduced.  

As quickly becomes clear, the dedicated teams at the forefront of genetic medicine are akin to detectives, finding the culprits behind diseases within our genes.  

Fittingly, then, the second section of The Genome Odyssey is entitled ‘Disease Detectives’ and covers the fascinating procedural work involved in solving rare, mysterious diseases and, by so doing, ending the agonising diagnostic “odysseys” that these patients have been sent on, such as was the case with Parker.  

Here, we meet other families such as the parents of Carson and Chase Miller, whose two young sons had been losing their mobility yet the reason for this was unclear. They were referred to Dr Ashley’s Center for Undiagnosed Diseases, which is itself part of a wider Undiagnosed Diseases Network in America, where both children and parents had their DNA sequenced. 

From this they found that Carson and Chase had both inherited one faulty copy of gene MECR from each of their parents. That, in itself, did not solve the ‘crime’ but this swiftly followed as the team “interrogated the evidence”, working out that this gene was essential to the smooth running of mitochondria—the “energy-producing powerhouses of the cell”—and, with other possible causes for the boys’ condition being ruled out, the wrongdoer in question. 

The case closed, attention could turn to treatment. Remarkably, it was deduced that a cheap over-the-counter supplement could compensate for the missing protein that MECR would normally produce. The boys were placed on this and, as Dr Ashley writes with delight, they have since stabilised and even shown signs of improvement.  

When not working on unsolved diseases, Dr Ashley deals with patients with genetic-based heart problems. This is the focus of the third part of The Genome Odyssey, ‘Affairs of the Heart’ and, again, presents many moving patient stories, such as that of a baby girl, Jazlene, whose dangerously abnormal heart rhythm was rapidly traced to a genetic cause. 

Thanks to the advent of cheap, fast genetic testing, new and ‘fine-tuned’ treatments can now be provided to patients—but this is only the beginning. 

The Genome Odyssey by Dr Euan Angus Ashley is a compelling work of popular science that explores the brave new world of genetic medicine as well as the personal stories of patients who have benefitted from this new era of medical treatments.The Genome Odyssey by Dr Euan Angus Ashley is a compelling work of popular science that explores the brave new world of genetic medicine as well as the personal stories of patients who have benefitted from this new era of medical treatments.
The Genome Odyssey by Dr Euan Angus Ashley is a compelling work of popular science that explores the brave new world of genetic medicine as well as the personal stories of patients who have benefitted from this new era of medical treatments.

The final section of The Genome Odyssey, ‘Precisely Accurate Medicine’, projects forward, examining where genomic medicine will progress from here. 

While gene therapy, replacing missing or faulty genes, is already available for a very limited number of conditions, ongoing research and refinements looks set to expand the scope for this treatment significantly in the coming years, potentially finding new, more effective ways to deal with a host of diseases including heart disease, multiple sclerosis, and certain types of cancer.  

Key to this, it turns out, will be sequencing the DNA of genetic “superhumans” whose unique genome protects them from certain diseases or provides other physiological advantages.  

Dr Ashley recounts, for instance, he story of Finnish cross-country skier Eero Mantyranta, whose blood contained far more oxygen-carrying red blood cells than the average person, allowing far greater levels of endurance.  

We also learn about American woman Sharlayne Tracy, who was found to have a superhuman ability to remove bad cholesterol from her body. Her genetic code has, in turn, led to new drugs for treating those who are genetically prone to high cholesterol. 

And in a very timely section, Dr Ashley reveals how genome sequencing can also be used on viruses to help us track and avoid future pandemics, just as it has been crucial in the development of vaccines for Covid-19.  

It’s amazing to discover just how far-reaching the unlocking of our genetic secrets will be for 21st century medicine, allowing doctors to move from reactive “disease care” to proactive “preventive health care” that will undoubtedly save many lives and allow us all to stay healthy for much longer.  

The Genome Odyssey tells this story in such an engaging way that the chapters just fly by. This is all helped by Dr Ashley’s personable, almost conversational style, his passion for the subject, and his admiration for the “heroes of this book”, as he describes them—his patients and their families.  

You come away from this highly informative, entertaining, and unforgettable scientific journey with the sense that we are heading into brighter days and all thanks to figures such as Dr Ashley who are tirelessly peeling back the mysteries of our DNA to overcome the diseases that have plagued us as long as mankind has existed.  

The Genome Odyssey: Medical Mysteries and the Incredible Quest to Solve Them (St. Martin's Press) by Dr Euan Angus Ashley is out now on Amazon in hardcover, eBook, and audiobook formats, priced £22.99, £9.49, and £20.47 respectively. For more information visit 


We speak with Dr Euan Angus Ashley, Associate Dean and Professor of Cardiology and Genetics at Stanford University, to find out more about his new work of popular science, The Genome Odyssey, and the genomic medicine revolution taking place right now.  

Q. Why was the decoding of the human genome essential for the development of genetic medicine? 

It’s hard to think of a time in the history of biomedical science when a technology has moved so fast, from requiring multiple countries, hundreds of people, and billions of dollars to something that can be routinely ordered by a physician in clinic for $500.  

But while the scientific narrative is exciting, it’s the human impact that made me want to write the book. I get to see every day how this technology can solve medical mysteries for kids and adults afflicted with devastating genetic diseases. I see how it can provide answers and provide a path to treatment (or if not, at least towards support groups and help). These are the medical “odysseys” of the title, a word derived from the epic Greek poem of the same name where the lead character takes 10 years and multiple shipwrecks and battles with, among others, one-eyed giants to get back to his home and his wife. 

Q. Why was the decoding of the human genome essential for the development of genetic medicine?

The genome is where it starts and ends. The genome connects us to every living organism on the planet. It contains the history of the human race. The history of your family. And yet each one is unique. Not even your identical twin has the same genome (though it’s very similar). Decoding the genome was a monumental feat in history akin to the Moon landing. But—little-known fact—it didn’t truly get finished until this year when many of the complicated regions and holes from 20 years ago got filled in. 

Q. Why does genetic-based medicine provide a better approach to curing diseases than our current models?

All diseases have a genetic component, but some diseases are mostly genetic. These are often referred to as Mendelian after the Austrian monk Gregor Mendel, who discovered the fundamental laws of genetics while cultivating pea plants. For these Mendelian diseases—with minimal environmental component (mostly nature, very little nurture) to understand—understanding the genetic basis of the disease is finally to understand, at the deepest level, how the disease comes about. It also has to be the starting point of finding truly effective medicines, something we refer to as “precision medicine”.  

Q. Are there any limits to how far genetic medicine can take us in the quest to eradicate human diseases?

Absolutely. For example, all diseases have an environmental component. Heart disease, for example, is half nature and half nurture. We have to pay attention to both. Also, some diseases are caused by pathogens and some by our immune system. Fortunately, for these diseases, genetic sequencing—of the pathogen or the immune cells—can also be very useful. 

Q. There have been numerous false starts in the field gene therapy. Do you think we should remain cautious for now about the future prospect of a genomic medicine revolution?

The false starts have mostly been with genetic therapy, where the early promise of the 1990s gave way after one or two high-profile deaths to 20 years of introspection and hard work; a time where our community really addressed the challenges head on. As a result, we are now in a golden age of genetic therapy. We still need to be cautious—this is powerful technology—but every day more and more diseases become susceptible to genetic approaches. 

Dr Euan Angus Ashley says that we are now living in a “golden age” of genetic therapy.Dr Euan Angus Ashley says that we are now living in a “golden age” of genetic therapy.
Dr Euan Angus Ashley says that we are now living in a “golden age” of genetic therapy.

Q. Some people get worried about the advent of genetic medicine, just as some were at one time concerned about genetically-modified crops. Is there any justification for such fears?

A. I think a better way to think about genetic therapy is like a more long-lasting form of a traditional medicine. Traditional medicines reprogram towards health how our cells work from the surface or through changing signals inside the cell. They work as long as the medicine is still present. Genetic therapy, on the other hand works, at the level of the genetic code (DNA) or its messenger (RNA). So therapies can be given perhaps every few months, or even like a vaccine, just once. That is very convenient! However, it also means we have to be very careful that we have tested the process thoroughly before testing it in humans. It is important to note that genetic therapy today is not about “designer babies”. Our community is universally opposed to this sort of genetic modification of our inheritance line. The current therapies are delivered to certain cells in one person at a time and those changes are never passed on to future generations.

Q. How has genetic medicine been instrumental in the fight against Covid-19?

A. Genetic sequencing has been the most fundamental technology in our fight against Covid-19. All the diagnostic tests we have are based at some level on knowledge of the genome of SARS-CoV-2. Also, all the vaccines approved to date are genomic vaccines, based upon the sequence of the virus. Sequencing also allows us to track the virus and its evolution to new variants around the globe. Most importantly, sequencing the virus will allow us to prevent the next pandemic by helping us understand which pathogens are most likely to cause disease and even perhaps allowing us to develop vaccines before the diseases the pathogens might cause ever come to light.

Q. The Genome Odyssey talks of ongoing studies into genetic superhumans and how their rare genes could result in all manners of new treatments in the coming years. In some respects, it sounds similar to the rush to find new medicinal plants in the Amazon rainforest. Is that a fair comparison, and what do you think will be the ‘fruits’ of these ongoing investigations, in terms of future treatments?

A. It’s a great question. In so many ways, the answer to many of our medical conundrums is likely out there in the world, whether in the rainforest or in the genomes of our fellow humans. Large-scale studies where altruistic individuals share their medical and genetic data for the good of the world allow us to identify a small number who are resistant to disease. By understanding why and how they are resistant we can start to design new medications that mimic these ‘superhuman’ qualities. With immune (antibody)-based and genetic-based therapies we can go from human genome to human medicine even faster than ever.

Q. Still on the topic of superhumans, do you think that we could one day all receive a simple jab that would give us the strength and stamina of an Olympic-medal athlete?

A. Well, just because something is possible doesn’t mean we should do it! In reality, however, we are so far away from knowing enough about the genetics of what makes our Olympians jump higher and run faster that even if someone wanted to genetically engineer superhumans, we simply don’t have the knowledge to do that. I think a much better idea is to focus on how to prevent devastating diseases and improve quality of life for everyone around the globe. Realising that some people are resistant to disease and dedicating ourselves to understanding that would be a far bigger service to humanity than making a few lucky (?) people run faster.

Q. Your book is full of incredible medical success stories that you have been involved with. If you were asked to single out just one, which one would it be, and why?

A. I think that the little baby, Astrea, whose heart stopped multiple times on the first day of her life was among the most memorable adventures I’ve ever been involved in. And not just for the fact we were able to sequence and analyse her genome faster than anyone had previously done—that was just the start. It was memorable because a whole village of scientists, entrepreneurs, geneticists, cardiologists, surgeons, and computer scientists from academia and industry came together to find answers for a little baby in distress. People simply dropped what they were doing and dedicated themselves to this. It really took my breath away.