Is Our DNA Mostly Junk? Study Says Only 8.2% of Human Genes are ‘Functional’
(NaturalSociety) Just two years ago, scientists involved in the Encyclopedia of DNA Elements (ENCODE) said that 80% of the human genome had some biochemical function, but a new study from Oxford University suggests that only 8.2% of human DNA does anything important. Is our ‘junk’ DNA really useless, or is there more to the story?
Many in the field of genetics have argued that the biochemical definition of ‘function’ was too broad, reminding us that just because an activity on DNA occurs, it doesn’t necessarily have a consequence. They suppose that for ‘functionality’ to occur, an activity on our DNA must matter.
The new study from Oxford supposed that evolution decides when activities on our DNA ‘matter’ and when they don’t. After all, over X number of years of mammalian evolution, our genome has avoided accumulative changes, suggestive that our DNA matters and that its function, however little we understand of it, is important.
Joint senior author Professor Chris Pointing of the MRC Functional Genomics Unit at Oxford University says:
“This is in large part a matter of different definitions of what is “functional” DNA – I don’t think our figure is actually too different from what you would get looking at ENCODE’s bank of data using the same definition for functional DNA.”
According to the Oxford study, if only 8% of our DNA is actually functional, then we would have to figure out, from a medical point of view, how mutations occur in order to avoid disease.
This argument butts up against some serious controversy regarding our ‘junk’ DNA. Some call junk DNA a myth, and others are determined to prove that the non-coding DNA serves an important purpose – otherwise, why would we have so much of it?
Susumu Ohno introduced the term ‘junk DNA’ in 1972. Since its naming, researchers have indicated that certain junk DNA sequences can have functional activity that is difficult to identify, or certain other junk DNA sequences could have had functional activity in the past. Since junk DNA seems to follow a very specific language code, not unlike the binary system which has helped develop modern computer software, others suggest that it contains ‘data-pending’ DNA for future evolution of the human species.
Read: Are GMOs Rewiring our DNA?
Dr. Gerton Lunter from the Wellcome Trust Centre for Human Genetics at Oxford University, the other joint senior author, states:
“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.”
He goes on to make a very bold statement considering how many times science has been wrong about the human form in the past. Medical assumptions and clinical errors abound in modern medicine. Even the placebo affect was once dismissed, even though it accounts for more spontaneous healings than all the pharmaceutical drugs ever created, combined:
“We found that 8.2% of our human genome is functional. We cannot tell where every bit of the 8.2% of functional DNA is in our genomes, but our approach is largely free from assumptions or hypotheses. For example, it is not dependent on what we know about the genome or what particular experiments are used to identify biological function.”
The authors of the study argue that we tend to have the expectation that all of our DNA must be doing something, but they believe this is false. They purport that hardly 1% of all human DNA accounts for the proteins that carry out critical biological processes, and the other 7% switches those processes on and off.
This is in direct opposition to findings at the Heart Math Institute, provided in large part by stem cell biologist Bruce Lipton. The findings show that our genes, including our ‘junk’ DNA, are influenced by more than just ‘on-off’ switches and a few proteins.
In fact, researchers have gone so far as to show that physical aspects of DNA strands could be influenced by human intention. The article, Modulation of DNA Conformation by Heart-Focused Intention – McCraty, Atkinson, Tomasino, 2003 – describes experiments that achieved such results.
While medical scientists continue to look at the humane genome to address health, they completely miss the point. As Lipton has said, “our health is not controlled by genes.” While medical professionals are wary of accepting such ground-breaking facts, they misunderstand the nature of how biology works.
Lipton and scientists in his camp offer another view:
“Medicine does miracles, but it’s limited to trauma. The AMA protocol is to regard our physical body like a machine, in the same way that an auto mechanic regards a car. When the parts break, you replace them—a transplant, synthetic joints, and so on—and those are medical miracles.
The problem is that while they have an understanding that the mechanism isn’t working, they’re blaming the vehicle for what went wrong. They believe that the vehicle, in this case our bodies, is controlled by genes. But guess what? They don’t take into consideration that there’s actually a driver in that car. The new science, epigenetics, reveals that the vehicles—or the genes—aren’t responsible for the breakdown. It’s the driver.”
Lipton sometimes refers to the work of Dr. Dean Ornish and his success in treating cardiovascular patients to prove his point.
“Dr. Ornish has taken conventional cardiovascular patients, provided them with important lifestyle insights (better diet, stress-reduction techniques, and so on), and without drugs, the cardiovascular disease was resolved. Ornish relayed that if he’d gotten the same results with a drug, every doctor would be prescribing it. That’s fine and dandy for people with heart disease, diabetes, or obesity, but what about cancer?
Even the strictest lifestyle changes don’t cure cancer in everyone. What about genetic predispositions to getting the disease? It used to be that we thought a mutant gene caused cancer, Lipton admitted, but with epigenetics, all of that has changed.”
Meanwhile, conventional medicine looks for the ‘rogue’ DNA so that they can cut it out, kill it with chemo, or prescribe it with expensive drugs. It seems that the other 92% of our genetic makeup deserves a little more inquiry.
The junk DNA argument from that paper is (paraphrasing):
1. Humans have 8.2% of their DNA in common with some other mammals.
2. Therefore that 8.2% of DNA must have existed in the last common ancestor of humans and those mammals.
3. They’re using neutral theory (standard in population genetics) so they assume that in time since those lineages diverged, evolution couldn’t have created much more function than that, so only around 8.2% of human DNA is functional.
You can read it yourself and see that’s actually what they’re arguing. Pasting the relevant bits:
“we address these issues by identifying and characterising sequence that has been constrained with respect to insertions and deletions for pairs of eutherian genomes over a range of divergences… From extrapolations we estimate that 8.2% (7.1–9.2%) of the human genome is presently subject to negative selection and thus is likely to be functional… Our estimate that 7.1%–9.2% of the human genome is functional is around ten-fold lower than the quantity of sequence covered by the ENCODE defined elements… This indicates that a large fraction of the sequence comprised by elements identified by ENCODE as having biochemical activity can be deleted without impacting on fitness… Nucleotide substitution rates in AR [ancient repetitive] sequences are very similar to estimates of the synonymous substitution rate (dS), hence our results appear insensitive to the choice of neutral sequence standard.”