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redOrbit Staff & Wire Reports – Your Universe Online
A newly discovered ‘second code’ hiding within our DNA is casting new light on how changes to DNA impact health and disease, according to a study published Friday in the journal Science. The new code is changing the way scientists read and interpret genetic instructions and mutations.
Since the genetic code was deciphered in the 1960s, scientists have assumed it was used exclusively to write information about proteins. In the current study, researchers at the University of Washington were shocked to discover that genomes actually use the genetic code to write two separate languages – one describing how proteins are made, and the other instructing the cell on how genes are controlled.
One language is written on top of the other, which is why the second language remained hidden for so long, the researchers said.
“For over 40 years we have assumed that DNA changes affecting the genetic code solely impact how proteins are made,” said study leader Dr. John Stamatoyannopoulos, associate professor of genome sciences and of medicine at UW.
“Now we know that this basic assumption about reading the human genome missed half of the picture. These new findings highlight that DNA is an incredibly powerful information storage device, which nature has fully exploited in unexpected ways.”
The genetic code uses a 64-letter alphabet known as codons. The UW team discovered that some codons, which they called duons, can have two meanings – one related to the protein sequence, and one related to gene control. These two meanings seem to have evolved in parallel with each other, with the gene control instructions appearing to help stabilize certain beneficial features of proteins and how they are made.
The discovery of duons has major implications for the way in which scientists and physicians interpret a patient’s genome, and will open new doors to the diagnosis and treatment of disease.
“The fact that the genetic code can simultaneously write two kinds of information means that many DNA changes that appear to alter protein sequences may actually cause disease by disrupting gene control programs or even both mechanisms simultaneously,” Stamatoyannopoulos said.
The work was part of the Encyclopedia of DNA Elements Project, also known as ENCODE, which aims to discover where and how the directions for biological functions are stored in the human genome.