Researchers study mutations in the genetic code to pin down functional DNA

Jul 25, 2014 20:13 GMT  ·  By

According to a study published in the journal PLOS Genetics, all humans are hoarders, be it with or without their knowledge. The thing that each and every one of us carries around despite not using it is so-called junk DNA.

The paper in question, authored by University of Oxford brainiacs, makes a case of how, according to evidence at hand, just 8.2% of human DNA actually does something. The remaining 91.8% has no important function.

Granted, the researchers admit that, every once in a while, some of this junk DNA might help regulate one gene expression or another. However, at the end of the day, the fact remains that our genome largely comprises trash.

“We tend to have the expectation that all of our DNA must be doing something. In reality, only a small part of it is,” says Dr. Chris Rands. “We found that 8.2% of our human genome is functional,” adds Dr. Gerton Lunter, as cited by EurekAlert.

The University of Oxford scientists behind this research project go on to detail that, of the 8.2% of the human genome that is functional, not all has the same importance. Thus, this DNA is in charge of performing various tasks.

More precisely, a little over 1% of human DNA sees to it that nearly all biological processes needed to ensure survival are carried out properly. The remaining 7% deals with activating and deactivating protein-encoding genes.

“The proteins produced are virtually the same in every cell in our body from when we are born to when we die. Which of them are switched on, where in the body and at what point in time, needs to be controlled – and it is the 7% that is doing this job,” explains Dr. Chris Rands.

In order to determine how much of the human genome is functional and how much is junk, the University of Oxford researchers resorted to studying mutations documented over the course of 100 million years of mammalian evolution.

The DNA found to have avoided accumulating all that many changes during this period of time was labeled as functional. This is because, when it comes to our genome, it is the DNA that has a job to do that avoids undergoing all that many transformations.

As Dr. Gerton Lunter with the University's Wellcome Trust Centre for Human Genetics puts it, “Throughout the evolution of these species from their common ancestors, mutations arise in the DNA and natural selection counteracts these changes to keep useful DNA sequences intact.”

In case anyone was wondering, this so-called junk DNA that researchers say that comprises 91.8% of our genome is basically leftover evolutionary material. The discovery that just 8.2% of our genome is functional is expected to lead to a better understanding of the genetic causes of various conditions.