As reported by Theguardian.com, Gerton Lunter, a senior scientist on the team, said that based on the comparisons, 8.2% of human DNA was "functional", meaning that it played an important enough role to be conserved by evolution.
More than 90% of human DNA is doing nothing very useful, and large stretches may be no more than biological baggage that has built up over years of evolution, Oxford researchers claim.
"Scientifically speaking, we have no evidence that 92% of our genome is contributing to our biology at all," Lunter told the Guardian.
Researchers have known for some time that only 1% of human DNA is held in genes that are used to make crucial proteins to keep cells – and bodies – alive and healthy. The latest study, reported in the journal Plos Genetics, suggests that a further 7% of human DNA is equally vital, regulating where, when, and how genes are expressed.
Though 8.2% seems a small portion of DNA to call functional, the meaning of the word is very specific. In the Oxford study, DNA is "functional" if it affects our reproductive fitness.
But other scientists take a broader view of what it means for DNA to be functional. Most of the 92% that Lunter's group says is not functional DNA is still active in some way in the body.
"Many [DNA] elements that play important roles in human disease are not evolutionarily conserved. Some of these have human-specific functions, some are involved in late-onset diseases like Alzheimer's, and others are simply missed by current comparative genomics methods," said Manolis Kellis, a computational biologist at MIT who was not involved in the study. "We cannot simply ignore the remaining 90% of the genome that is not evolutionarily conserved."
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