Despite all the publicity, Human Longevity Inc. is a personalized medicine company rather than a longevity science company, intended to be the seed for a new industry that provides an incremental advance on present day customization of medicine through use of genetics. As I've said for a while now, this sort of application of genetics is not the path to significant enhancement of human longevity. All that this industry can do in the near term is inform us more accurately as to why the natural variations in human longevity exist, and provide ways to move someone from a slightly lower life expectancy bracket into a slightly higher life expectancy bracket. The latter is something that you can do for yourself today by undertaking exercise or calorie restriction. This is fiddling small change in the bigger picture. In that bigger picture, it is clear that we all age for the same underlying reasons: exactly the same forms of accumulated cell and tissue damage drive aging in all of us. Effective therapies to treat the causes of aging - and thereby produce radical life extension of decades at first and centuries later - will repair this damage, and will thus be exactly the same for everyone, with a massive scale of production to drive down the costs. The expensive undertaking of highly personalized medicine is simply not all that important when it comes to rejuvenation and the future of human longevity.

Craig Venter's latest venture, Human Longevity, Inc., or HLI, creates a realistic avatar of each of its customers - they call the first batch 'voyagers' - to provide an intimate, friendly interface for them to navigate the terabytes of medical information being gleaned about their genes, bodies and abilities. Venter wants HLI to create the world's most important database for interpreting the genetic code, so he can make healthcare more proactive, preventative and predictive. Such data marks the start of a decisive shift in medicine, from treatment to prevention. Venter believes we have entered the digital age of biology. And he is the first to embark on this ultimate journey of self-discovery. HLI has now submitted an analysis of its first 10,000 human genomes for publication, passing a milestone in creating what Venter hopes will be the world's largest, most comprehensive database of information to help transform healthcare and find answers to one of the oldest questions of all: is it possible to defy the ravages of ageing?

In 1998 Venter unveiled the privately funded Celera Genomics, which incurred the wrath of his peers in the public genome programme. He found himself battling with some of the world's biggest scientific institutions. The race propelled him onto front pages around the world when Celera unveiled its first human genome alongside the publicly funded version. Today, everybody in the field wants genomics to be part of medicine, he says. When it came to deciding where to bring about that merger, and finish the job that he started with Celera, Venter returned to the West Coast. On the coast, occupying land owned by the university, Venter has built the Californian campus of his not-for-profit J. Craig Venter Institute. He also set up Synthetic Genomics. This company is trying to understand the basic software of life and rewrite it to create novel organisms that can produce fuel, chemicals and medicines.

To synthesise the insights from these ventures, Venter founded HLI with stem cell pioneer Robert Hariri and technology entrepreneur Peter Diamandis, founder of the XPRIZE Foundation. Venter regards HLI as Celera on steroids. "The whole idea behind this is to identify the risk, then modify that risk so that you end up with longer periods of normal health. That is what the patient wants too. The patient does not want just more years but quality years." HLI started out stockpiling human genomes by sequencing them for partners that needed the data for research. This is only one ingredient of what Venter hopes will become the biggest genotype-phenotype database in the world. "Right now, we know less than 1 per cent of the genome in terms of how to really interpret it. Even with that, that's extremely valuable in being able to start this new preventative medicine paradigm where this information can help people understand their own health risk and hopefully save a lot of lives." So far, HLI has amassed the sequences of around 20,000 whole genomes, says Venter. But, of course, he wants even more. The company has room for more sequencing facilities on its third floor and is considering a second centre in Singapore, planning to rapidly scale to sequencing the genomes of 100,000 people per year - whether children, adults or centenarians, and including both those with disease and those who are healthy. By 2020, Venter aims to have sequenced a million genomes.

Venter wants to move from basic genetics to impacting individual lives "very directly. The most important part of that is nothing to do with the genome directly, but measuring phenotype and physiology and understanding their medical risk. That is what the microbiomes of its patients too - their cargo of gut microbes, which play a key role in health. Most valuable of all, Venter wants to link these various -omes to patients' phenotypes: their anatomy, physiology and behaviour. To do this, standard body measurements, online cognitive tests and blood samples are taken. The Health Nucleus adds yet more data using non-invasive tests. My tour begins with the room where HLI conducts a total body scan to create the avatars that inhabit its app. We pass through a succession of white rooms. There's one where visceral fat (which is linked to type 2 diabetes and cardiovascular disease) muscle volume, grey matter, white matter and more.

"We will be developing the evidence around this to make the case for preventive medicine." HLI has more work to do, such as organise a randomised controlled trial to compare the outcomes of people who get the tests with those who do not. Not everyone is convinced that HLI's testing will translate into improved health. Venter says that criticisms stem from the conservative nature of the medical community, notably when it comes to keeping the costs of screening under control. "That is the medical establishment saying: we want to keep doing what we do, we want to see people after they develop symptoms and have something wrong with them. The 'human longevity approach' is the exact opposite."