Noncoding DNA Becoming UnderstoodCategory: Science & Technology
Posted: September 10, 2012 09:30AM
Perhaps one of the most ambitious projects of modern times is the one to map the entire human genome. Already the efforts to do so have made profound discoveries, such as identifying the segments of DNA that code for proteins, but there are still more discoveries to be made. That portion of DNA accounts for only 1% of all of the information in the molecule, and now researchers from several dozen labs and hundreds of researchers across the planet, including MIT, have determined what another 80% is for.
While proteins are responsible for the many activities of a cell, they have to be properly controlled. When proteins are left unchecked, serious diseases such as diabetes and lupus can develop, and it turns out that 80% of the genome is specifically for the regulation of proteins and other biological chemicals. Interestingly, the effects a specific portion of this regulatory or noncoding portion of DNA will vary from cell type to cell type, so a sequence that stops one protein in a skin cell may activate a protein in a liver cell (just for example).
This discovery also is important for understanding the history of the human genome and how it compares to other species. A recent paper showed that about 5% of this noncoding DNA is constant across mammals, while an additional 4% is conserved just across humans. This DNA is likely the result of recent mutations that have survived evolution, such as color vision and nerve growth pathways.