Deoxyribonucleic acid, better known as DNA, is how genetic information is recorded in every living cell. Messenger RNA (mRNA) molecules turn DNA into proteins through a process called translation. However, only one per cent of each DNA strand can be translated. This means the other 99 per cent doesn’t code for a specific protein in the body. These non-coding regions, known as introns, have a function that is still unidentified.

Previously, introns were widely considered to be ‘junk DNA.’ Some scientists still believe they are a vestigial part of DNA that was useful in the past but became functionally insignificant as evolution proceeded. However, many biologists now find this explanation unsatisfactory, as introns are highly preserved in large amounts throughout many generations.

Dr. John Mattick, a biologist at the University of Queensland and world class expert on introns, has another theory. “The reason why humans and other complex organisms have so much non-coding DNA is because they need so much more information to program the assembly of the components, which are encoded by conventional genes to create something like you or me,” he said. Mattick hypothesizes that non-coding DNA acts as a blueprint that tells proteins and coding DNA how to operate. He also theorizes that it’s possible to have a system working simultaneously alongside the flow of information from DNA to mRNA to proteins, which he calls the DNA-iRNA (informational RNA) system. Introns could play a role in this second system, which would increase the options for genetic programming.

Introns may be a pre-requisite to the emergence of more complex life. DNA of more primitive cell types contains only a small amount of introns, whereas more complex types of cells contain large quantities. Dr. Mattick argues “the fact that the Earth was limited to unicellular or at best colonial life forms for most of its [more than] 3,500 million year biological history, and that multicellular organisms arose recently from within a relatively narrow taxonomic group, characterized by high intron content, is consistent with this [the role of introns as the precursor of complex life].”