COLLEGE STATION, Texas, July 28 (UPI) -- U.S. scientists have discovered that cells have more than one way to protect themselves from their own potentially destructive DNA components.
Up to 95 percent of human DNA is thought to be so-called junk DNA, the useless remnants of hundreds of thousands of years of evolution. Scientists think RNA molecules are used to silence the extra DNA and keep it from affecting chromosomes and causing disease.
Now, researchers at Texas A&M University and the University of Oregon said they have found that, even in the absence of RNA, cells still can neutralize the junk DNA. They used mutant versions of the mold Neurospora crassa. Although the mutants were designed to be unable to produce any key components of the junk-DNA silencing mechanism, the altered mold cells did so anyway.
"What we have shown," said Rodolfo Aramayo, associate professor of biology at Texas A&M, "is that cells have evolved more than one way to do the same thing -- and this is important, because similar mechanisms might be present in human cells."