'Junk DNA' concept debunked by major study
6 Sep 2012
The most detailed analysis of the human genome suggests that more than 80% has an active biologically function.
According to the researchers in the Encode (the Encyclopedia of DNA Elements) project, a larger proportion of the human genetic code is biologically active than previously thought.
The project, launched in 2003, had the goal of identifying all the functional elements of the human genome. A pilot project looking at 1% of the genome was published in 2007.
As part of the latest study, Encode scientists analysed all three billion pairs of genetic code that make up human DNA. Only a small percentage of these are codes for proteins.
The roles and functions of the remaining genetic information were so unclear to scientists that they were referred to as “junk DNA.”
However, the project revealed that more than 80% of the human genome is associated with biological function.
The study showed that proteins switch genes on and off regularly - and can do so at distances far from the genes they regulate.
It also determined sites on chromosomes that interact, the locations where chemical modifications to DNA can influence gene expression, and how the functional forms of RNA can regulate the expression of genetic information.
The results establish the ways in which genetic information is controlled and expressed in specific cell types and distinguish particular regulatory regions that may contribute to diseases.
The results will have a significant impact on medical science. For example, recent genetic studies have revealed many genomic locations that can affect a person’s susceptibility to common disease.
The Encode data show that many of these regions are involved in gene regulation, and the data provide hypotheses for how variations in these regions can affect disease susceptibility.
