Human instruction book not so simple: studies

WASHINGTON (Reuters) - An in-depth examination of the human DNA map has turned basic biology concepts upside-down and may even rewrite the book on evolution and some causes of disease, researchers said on Wednesday.

They found there was far more to genetics than the genes themselves and determined there was no such thing as "junk DNA" but that some of the most useless-looking stretches of DNA may carry important information.

Thirty-five teams of researchers from 80 different organizations in 11 countries teamed up to share notes on just 1 percent of the human genome.

Their findings, the start of the Encyclopedia of DNA Elements or ENCODE Project, were published in the journals Nature and Genome Research.

"This is a landmark in our understanding of human biology," said Dr. Francis Collins, head of the National Human Genome Research Institute, which funded much of the work.

When the human genome was published in 2003, some scientists voiced surprise that human beings had only about 30,000 genes. Rice, for instance, has 50,000.

The new study confirms what many genetics experts had suspected -- the genes are important, but so is the other DNA, the biological code for every living thing.

What they discovered is that even DNA outside the genes transcribes information. Transcription is the process that turns DNA into something useful -- such as a protein.

ACTION OUTSIDE THE GENES

Much of this action is going on outside the genes in the so-called regulatory regions that affect how and when a gene activates, Collins said.

The researchers discovered 4,491 of these so-called transcription start sites, "almost tenfold more than the number of established genes," they wrote in the Nature paper.

Ewan Birney of the European Molecular Biology Laboratory's European Bioinformatics Institute in Cambridge said this helped explain how such a complex creature as a human arose from just four letters of code repeated over and over.

"The junk is not junk. It is really active," Birney told reporters. This could be useful in understanding and treating disease.

"One could imagine that that actually could be a good thing because it would tell you that there is a subtle tweaking of the expression of that particular gene, and therefore that particular protein in a person at high risk -- they are making a little too much or not quite enough," Collins added.

Drugs might easily be designed to compensate, he said.

The researchers did find some DNA that appears to do nothing, and it can mutate without causing any damage.

Collins likened these stretches of DNA to boxes in the attic.

"It is not the sort of clutter that you get rid of without consequences because you might need it. Evolution may need it," he said.

That little extra padding might be just what an animal needs to adapt to some unforeseen circumstance, the researchers said. "They may become useful in the future," Birney said.