I once had a professor who claimed that Viagra was the logical endpoint of all science. “We did it!” he exclaimed, one day in class. All those millions of years ago, he argued, the first real attempt at a medical experiment probably came in the form of a thick-browed Neanderthal chewing on a leaf and hoping for some aphrodisiac effects. The professor claimed that the quest to control our own sexual natures was the oldest in human history, but I always thought there was something much more primal. While his was an amusing thesis, it seemed that the real ultimate quest in science was to figure out just what in the hell we are. More than the quest to control our natures, it is the quest to understand that nature that has truly obsessed mankind.

Thus, it seems that the most logical point in scientific history to name as our “We did it!” moment is the sequencing of the first human genome. After hundreds of thousands of years of prodding, both intellectually and physically, after the rise of both human dualism and human dissection, it took little more than a century to build from the discovery of DNA to the total sequence of the human blueprint. After all that time, and so many productive scientific lives wasted on non-starter theories of human nature, we finally had our answer.

But how to read it? In probably the most frustratingly anti-climactic victory in scientific history, the sequencing of the human genome told us virtually nothing of use or interest. One of DNA’s primary human avatars, Craig Venter, has been notoriously blunt about this, calling the raw sequence data from the human genome “useless” and chiding the public for having the audacity to get caught up in the fervor of optimism that he himself helped to create.

Most sequence data was encrypted, albeit unintentionally, with a code infinitely more complex than any computer cypher; the encryption was done at the DNA level, with promoters and regulatory sequences, at the RNA level, with splicing and processing, and at the protein level, with post-translational modifications and the rightly dreaded process of protein folding. There were simply too many gaps between the DNA sequences and their real-world impacts, and we had painfully few tools with which to get across.

And yet, we knew the genome was important. Imagine if physicists had happened to discover every one of the atomic and quantum particles known today — from baryons to bosons — but they had somehow made that discovery in 1850. Though they would know the momentous nature of their work, a down quark is useless to someone who has yet to invent the transistor. In a very real way, this is what happened to molecular biologists. We found our bosons before we’d invented our super-colliders, or indeed even figured out why such devices might be helpful.

So we built super-colliders. It became clear early on that one genome wasn’t going to be enough, because the only way across those gaps nature had set between DNA and phenotype was to study the effects of DNA on the statistical scale. This meant not just sequencing more humans, but non-human species as well. Molecular biology became abruptly about comparison — comparison between versions of a gene, comparison between individuals in a species, comparison between species in an evolutionary branch. We’d been sequencing the little circular genomes of bacteria and other simple organisms for a while at that point, but it was only after we put out the genome of James Watson that things really starting taking off.

Next page: DNA sequencing on-the-cheap…