Sat, Jan 02, 2010 - Page 9 News List

The decade we learned the language of life

Mapping 6 billion genes has sparked a new age of biological technology with massive potential

By Ian Sample  /  THE GUARDIAN , LONDON

It was the decade that launched a new age of science, and it came as no surprise. Researchers had foreseen the rise of biology in the 1990s and expected nothing less than a transformation of modern medicine and giant leaps in our knowledge of life on Earth.

They cannot be disappointed. In the last 10 years, scientists have looked deeper into the mechanics of life than ever before. They have learned how molecules come together to make living organisms, how biological glitches cause common diseases, and have come within a whisker of creating new lifeforms in the laboratory.

Genetics was at the heart of the revolution. Scientific and technological advances allowed researchers to read every letter of an organism’s genome. The letters make genes, which are the templates for proteins that make cells. And the cells, in the tens of trillions, build the animals and plants around us.

The first major achievement came in 2001 when the 13-year, US$4 billion human genome project produced the first draft of the human genetic code. The huge task became a race between a global consortium of publicly funded scientists and an American genetics pioneer, Craig Venter. It was, said Venter, “the most important scientific effort humankind has ever mounted.”

The human genome project put the essence of humanity into numbers. Our genetic code is 6 billion letters long, grouped into around 25,000 genes. Francis Collins, head of the public genome project, declared it the first draft of our own book of life.

“We’ve read it from cover to cover and we’ve discovered some pretty amazing surprises,” he said.

Scientific revolutions have a long history of taking humans down a peg or two, and the genetics revolution was no different. As more organisms submitted to genetic analysis, scientists learned that humans were not so different from other organisms. We share more than 95 percent of our genes with chimps and around 30 percent with bananas. Nematode worms, which grow to 1mm long, have a similar number of genes to humans.

Today, scientists have read the genomes of more than 180 organisms. They include the malaria parasite, Plasmodium falciparum, and a host of other pathogens, as well as rice, maize and other food crops. The information gives scientists insights to combat disease and make dietary staples more resilient.

Genetics came into its own when sequencing technology became cheap and fast. It allowed scientists to compare the genomes of tens of thousands of sick and healthy people and find flaws in DNA that lead to a vast range of ailments. The list so far includes defects linked to diabetes, high blood pressure, rheumatoid arthritis and heart disease.

The role of genetics in disease has turned out to be more subtle than many scientists had hoped. Only rarely does one gene cause one ailment. More often several genes play a role, with each raising the risk of illness. Who falls sick is down to a complex interplay between a multitude of genes and environmental factors such as diet and lifestyle.

Scientists now know the picture is more complicated still. Almost every cell in the body contains the genetic code in full, but every tissue uses it differently. Some genes are turned up while others are silenced to keep heart cells beating and brain cells firing. Sometimes, this exquisite control breaks down, causing cancer and other diseases. A global effort to understand this “epigenome” is under way.

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