'Junk' All That Separates Humans From Chimps

If we're 99% the same, what makes us different? (Reuters/AP)

We all are the one percent, apparently.

Scientists have long been baffled by the genetic similarities between humans and chimpanzees, which share up to 99 percent of the same DNA despite our vast differences in appearance and ability -- baffled until now, that is. Researchers have determined that the only thing that separates us from chimps is a tiny bit of “junk DNA.”

Led by Georgia Tech professor of biology John McDonald, a new study has verified that while the sequence of genes between humans and chimpanzees is nearly identical, Chimpanzees have certain gaps in their genome. In humans, those gaps are filled with what is known as “junk DNA.” The findings are reported in the most recent issue of the online, open-access journal Mobile DNA.

The research could go a long way in answering a universal question -- what makes us so different?

"Let’s say intelligence is your ability to compose poetry, symphonies, do art, math and science," astrophysicist Neil deGrasse Tyson explained at a talk at St. Petersburg College. “Chimps can’t do any of that, yet we share 99 percent DNA.”

“Everything that we are, that distinguishes us from chimps emerges from that one-percent difference,” DeGrasse continued.

For years, scientists assumed the opposite, that this junk DNA did very little. By definition, the sequences have had no known biological functions, such as encoding for protein sequences.

But McDonald’s research indicates these bits of seemingly random code act as important regulators within the human genome, serving as on and off switches, activating important genes and regulating how they are expressed.

"Transposable elements were once considered 'junk DNA' with little or no function. Now it appears that they may be one of the major reasons why we are so different from chimpanzees,” McDonald said.

"Our findings are generally consistent with the notion that the morphological and behavioral differences between humans and chimpanzees are predominately due to differences in the regulation of genes rather than to differences in the sequence of the genes themselves, “McDonald said.