A study of the 98 percent of the human genome that is not, strictly speaking, genes suggests more than three-quarters of entire allotment of DNA is active at some point in our lives, The Washington Post reported Wednesday.
"This concept of 'junk DNA' is really not accurate," said Richard Myers, one of the leaders of the 400-scientist Encyclopedia of DNA Elements Project, nicknamed Encode.
"It is an outdated metaphor to explain our genome."
The Human Genome Project had revealed human cells contain only about 21,000 genes, far fewer than most biologists had predicted, and those genes comprised just 2 percent of the cell's DNA.
Parts of the genome once thought to be "junk" may have an important role in regulating genes, switching them on and off, influencing their output, controlling their timing and coordinating their activity with other genes, the new findings suggest.
"There is a modest number of genes and an immense number of elements that choreograph how those genes are used," said Eric D. Green, director of the National Human Genome Research Institute, the federal agency that paid for the research.
At least 4 million sections of the genome are involved in manipulating the activity of genes, researchers suggest.
"The genome is just alive with stuff. We just really didn't realize that before," Ewan Birney of the European Bioinformatics Institute in England said.