7 May 2004

In a world first, scientists from The University of Queensland's Institute for Molecular Bioscience (IMB) have uncovered a new class of genetic elements with the potential to radically alter our notions of how the genome "comes to life" to form humans.

What has been discovered is despite hundreds of millions of years of evolution there are thousands of these genetic elements in humans, rats and mice that remain identical.

The IMB team headed by Professor John Mattick, in collaboration with a group led by Dr David Haussler from the University of California at Santa Cruz, believe these genetic elements may form part of a sophisticated and previously unrecognised instruction manual for the assembly of complex organisms like humans.

Professor Mattick said the chance of these sequences remaining the same through millions of years of evolution was so small, there had to be a critical but as yet unknown evolutionary reason to keep these sequences identical.

"Highly conserved regions of DNA are good indicators of biological importance and it is likely that these elements are essential for vertebrate and mammalian development," Professor Mattick said.

"If so, it strengthens our argument that ‘junk' DNA contains complex regulatory and programming information, challenging current theories on the genetic structure of complex organisms."

He said a good analogy was the assembly of an aircraft where not only must the nuts and bolts – or in this case ‘genes' – be itemised but an instruction manual containing an enormous amount of information is required for construction and correct operation.

"We compared the genomes of humans, rats and mice only to find there were thousands of absolutely identical DNA segments," he said.

"Further investigation also showed that many of these segments were also preserved in chickens and fish.

"No other areas of DNA are as fiercely protected from change, not even the regions of DNA encoding proteins (the genes) exhibit this degree of conservation."

Until now, scientists generally thought all the relevant genetic information required to make a human was contained in the 1.2% of DNA that encodes for proteins.

However Professor Mattick and his team believe human complexity cannot be totally contained in genes alone and the remaining 98.8% of our DNA, often referred to as junk, plays a vital role in telling our genes what to do.

"Rather than thinking of genes as oases in the desert of junk DNA, we propose that they are islands floating in a sea of regulatory information," Professor Mattick said.

"Our discovery will open up a new field of research into the true nature of human genetic programming and how we grow and develop differently from each other."

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