When Sydney geneticist John Mattick suggested junk DNA was anything but rubbish he was challenging an assumption that had underpinned genetics for 50 years.
”The ideas I put forward 10 years ago were quite radical but I thought I was right,” Professor Mattick said.
He was. And tomorrow he will become the first Australian honoured with the Chen Award for distinguished academic achievement in human genetic and genomic research, awarded by the Human Genome Organisation.
For decades after James Watson and Francis Crick discovered DNA was a double helix, scientists believed most genes were the written instructions for proteins, the building blocks of all body processes. The assumption was true for bacteria but not complex organisms like humans, said Professor Mattick, the new executive director of the Garvan Institute.
In humans, more than 95 per cent of the genome contains billions of letters that do not make proteins, called non-coding DNA. ”When people bumped into all this DNA that didn’t make proteins they thought it must be junk,” he said. But Professor Mattick felt it was unlikely that useless material would survive hundreds of millions of years of evolution.
He found that the non-protein-coding sections of DNA had a function, to produce RNA.
“The obvious and very exciting possibility was that there is another layer of information being expressed by the genome – that the non-coding RNAs form a massive and previously unrecognised regulatory network that controls human development.”
Many scientists now believe this RNA is the basis of the brain’s plasticity and learning, and may hold the secret to understanding many complex diseases.