It’s been compared to a star chart that reveals a glimpse into a new world.

Some say it is like a parts list for what makes us human.

Still others describe it as the equivalent of a Google Earth map of the human genome, an incredibly detailed description that takes researchers to the street level of our DNA.

Though the analogies proffered by scientists differ, they all agree the deluge of data released Wednesday by an international consortium is so groundbreaking it will trigger new editions of science textbooks and accelerate the pace of medical discovery across the globe.

“It is going to impact every single molecular biologist in the world,” says Aled Edwards, a professor at the Banting and Best department of medical research at the University of Toronto.

The project that uncovered this treasure trove of data is called Encode, which stands for Encyclopedia of DNA Elements. Launched in full in 2007, it involved more than 400 scientists from 32 labs around the world who took part in 1,600 sets of experiments on 147 types of tissue.

The dozens of papers describing how the scientists conducted the research and the impact of their findings were published last week in a group of top journals, including Science and Nature.

The amount of data is enormous. But boiled down, the take-home message is that the human genome is much more active than scientists previously thought.

“We now have much more detail on the DNA code,” Edwards says. “How it is used, how it is organized, what parts of the code regulate other parts of the code…”

From that vast undertaking, scientists learned there are 3 billion base pairs that make up the iconic, twisting ladder of our DNA. They also pinpointed about 20,000 genes — a fairly small number, most scientists believed, for running something as complex as the human body.

“The protein-coding parts of those genes only comprised about 1 per cent of the genome,” says Mark Gerstein of Yale University. “One of the immediate mysteries was: ‘What is the other 99 per cent doing? What is really going on in the whole genome?’”

Those questions led to Encode, which began as a pilot project in 2003.

The answers scientists have since found are striking.

Once considered “junk” DNA — that 99 per cent lying outside the 20,000 genes that code for proteins — is actually packed with millions of switches that control the behaviour of organs, tissues and cells.

These switches — there are at least 4 million of them — are the regulatory controls that determine which particular gene is used in a cell, and when.

Dr. Thomas Hudson, president and scientific director of the Ontario Institute for Cancer Research, says the switches govern, for example, whether a cell will become a liver cell or a brain cell. The finding, he says, helps answer why individual humans are so different despite sharing the same general DNA blueprint.

Encode revealed that 80 per cent — not just 1 per cent — of the human genome has a function.

“It’s amazing,” says Hudson, who worked on the Human Genome Project while at the Massachusetts Institute of Technology. “We went from understanding 1 per cent to 80 per cent. While we still don’t know all of what it does, we see there is activity in these regions of the genome.”

Dr. Steve Scherer, a senior scientist at the Hospital for Sick Children and professor of genome sciences at the University of Toronto, describes Encode’s impact on medical science in this way:

“The human genome sequence generated a two-dimensional flat map of our species DNA equivalent to early pre-Columbus maps. Our own. . . map added the third-dimension. . . analogous to adding mountains and valleys to the round planet.”

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In 2006, Scherer led an international team of researchers to a groundbreaking discovery that revealed many hundreds of genetic variations called copy number variants (CNVs) hidden within the human genome. CNVs are large segments of DNA that either have an extra or missing part, as opposed to a single pair.

Scherer says the new Encode map “lays the functional characteristics on DNA, similar to the trees and lakes and rocks on the earth. In essence, we now have a Google Earth map of the human genome.”

Scientists from around the world — and many in Toronto — are now using the data generated by Encode to learn more about evolution and human disease.

The data is publicly available and free, something Edwards says should be applauded. The intense and coordinated international collaboration saved millions of dollars and shaved years off the time it would take for individual labs to create such an annotated map of the human genome.

Once there are detailed instruction manuals for the switches that, say, influence whether or not a person gets a form of cancer, scientists can then work backward to find out what went wrong, and where, to hopefully identify ways to repair or resolve the problem.

Some diseases, such as cystic fibrosis, are caused by mutations in a single gene. But many other common diseases, including multiple sclerosis, rheumatoid arthritis and cancer, are the result of changes in the genetic switches — the so-called junk DNA — and not the genes themselves.

The Encode project helps researchers home in on particular regions of switches that appear critical for a particular disease. Hudson, for example, is using data generated by Encode to investigate the genetic underpinnings of colon cancer.

The hope is that understanding the regulatory function of the switches, and how they are influenced by a person’s environment, will lead to new drugs and innovative therapies.

Gerstein, an Encode researcher and a professor of biomedical informatics at Yale University, says a major application of the findings is in the field of personal genomics.

“In the future, everyone will have their genome sequenced as a matter of course in their medical care,” he says. That personalized map, he adds, will be used to predict a person’s risk of getting particular diseases and could help to design individualized drugs or therapies.

An exciting prospect, and one that mirrors the hopes triggered by the completion of the Human Genome Project.

In a few more years, scientists will have created an even higher resolution map of the human genome, complete with detailed schematics of how the long stretches of DNA function, revealing new insights and bringing those hopes closer to reality.

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