New Nucleotides Identified in Human DNA

The human recipe just got complicated: It turns out there are more ingredients in us than we thought.

In high school science, we were taught of the four basic units that make up DNA -- adenine, guanine, thymine and cytosine. When scientists talk of DNA sequencing, it's written as strings of these units: ATCGGTGA, and so on.

NEWS: Personal DNA Tests Arriving in Stores Near You

In recent years, scientists expanded that list of nucleotides from four to six. And in a study published online in the most recent issue of Science magazine, researchers from the University of North Carolina School's medical school have discovered the seventh and eight bases of DNA.

DNEWS VIDEO: Did you know you can trace bomb builders through the DNA left on their bombs?

But the meaning of this extra ingredient in the alphabet soup that makes us who we are isn't as simple as A, B, C.

"Before we can grasp the magnitude of this discovery, we have to figure out the function of these new bases," said Yi Zhang, biochemistry and biophysics professor at UNC's Howard Hughes Medical Institute.

Zhang arrived at his discovery by playing around with the chemical makeup of the base cytosine; by adding a new chemical tag -- called a methyl group -- to the base it became those fifth and sixth units. This process, called methylation,causes the DNA's double helix to fold even tighter upon itself.

WIDE ANGLE: All About DNA

Demethylation describes the removal of a chemical group from a molecule, a process that led to the new 7th and 8th units -- they've been given the ugly names 5-formylcytosine and 5 carboxylcytosine. (The fifth base -- 5 methylC -- and the sixth base -- 5 hydroxymethylC -- have equally ungainly names, to be fair.)

"These bases represent an intermediate state in the demethylation process," he explained.

For Subscribers

FOR SUBSCRIBERSCBP leaders cut out of Trump ad buy decision

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

For Subscribers

FOR SUBSCRIBERSCBP leaders cut out of Trump ad buy decision

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

Once better understood, Zhang hopes his discovery could someday advance the field of stem cell research. By demethylating DNA, it may be possible to reprogram adult cells to make them act like stem cells.

It could also inform cancer research, as it could give scientists the opportunity to reactivate tumor suppressor genes that had been silenced.