Since the genetic code was deciphered in the 1960s, researchers have assumed that it was used exclusively to write information about proteins.
But biologists have suspected for years that some kind of epigenetic inheritance occurs at the cellular level. The different kinds of cells in our bodies provide an example. Skin cells and brain cells have different forms and functions, despite having exactly the same DNA.
NO SUCH THING AS JUNK DNA
The human genome is packed with at least four million gene switches that reside in bits of DNA that once were dismissed as “junk” but it turns out that so-called junk DNA plays critical roles in controlling how cells, organs and other tissues behave. The discovery, considered a major medical and scientific breakthrough, has enormous implications for human health and consciousness because many complex diseases appear to be caused by tiny changes in hundreds of gene switches.
As scientists delved into the “junk” — parts of the DNA that are not actual genes containing instructions for proteins — they discovered a complex system that controls genes. At least 80 percent of this DNA is active and needed. Another 15-17 percent has higher functions scientists are still decoding.
Recent findings in the journal Science may have big implications for how medical experts use the genomes of patients to interpret and diagnose diseases, researchers said.
The genetic code uses a 64-letter alphabet called codons. Dr Stamatoyannopoulos with co-authors were stunned to discover that some codons, which they called duons, can have two meanings. One describes how proteins are made, and the other instructs the cell on how genes are controlled.
The newfound genetic code within deoxyribonucleic acid, the hereditary material that exists in nearly every cell of the body, was written right on top of the DNA code scientists had already cracked.
Rather than concerning itself with proteins, this one instructs the cells on how genes are controlled.
Its discovery means DNA changes, or mutations that come with age or in response to vibrational changes within the DNA, may be doing more than what scientists previously thought.
“For over 40 years we have assumed that DNA changes affecting the genetic code solely impact how proteins are made,” said lead author John Stamatoyannopoulos, University of Washington associate professor of genome sciences and of medicine.
“Now we know that this basic assumption about reading the human genome missed half of the picture,” he said.