Junk DNA

DNA-233x300“The discovery in the 1970s that only a tiny percentage of our DNA codes for proteins prompted some prominent biologists at the time to suggest that most of our DNA is functionless junk.  Although other biologists predicted that non-protein-coding DNA would turn out to be functional, the idea that most of our DNA is junk became the dominant view among biologists.  That view has turned out to be spectacularly wrong.”  Jonathan Wells, The Myth of Junk DNA, p. 9

“The arguments by Dawkins, Miller, Shermer, Collins, Kitcher, Coyne and Avise rest on the premise that most non-protein-coding DNA is junk, without any significant biological function.  Yet a virtual flood of recent evidence shows that they are mistaken:  Much of the DNA they claim to be ‘junk’ actually performs important functions in living cells.” Ibid., p. 27

“A whole new class of genes has been discovered which do not encode proteins, but encode functional RNAs.  Such genes have escaped recognition in computer searches for protein-coding sequences, and so have been overlooked as true genes.  But they are true genes, and they probably comprise a large part of the genome (Mattick, 2001; Dennis, 2002; Storz, 2002).  They are just now being discovered within DNA regions that were previously dismissed as ‘junk.’  J. C. Sanford, Genetic Entropy and the Mystery of the Genome, p. 38, 39

Decoding the Debris

For decades, evolutionary scientists have ignored “junk” DNA that supposedly littered our genetic sequence. Now that they’ve finally realized their mistake, they’re opening new fields of discovery.

Georgia Purdom, Answers magazine, July-September 2014, p.37f

For decades most of the human genome (98 percent) has been considered “junk” DNA, with only about 2 percent coding for proteins. The geneticist Susumu Ohno first coined the term junk DNA in 1972. He stated, “The earth is strewn with fossil remains of extinct species; is it a wonder that our genome too is filled with the remains of extinct genes?”

That perspective is changing rad­ically. When the first version of the human genome was reported in 2001, scientists found far fewer genes than they had expected. (Genes are packets of information in the DNA responsible for making proteins.) Although nearly all cells in the body have the same DNA content, they, need to make certain proteins at certain times and under certain conditions. What regulatory processes are keeping all this genetic activity straight? To answer that ques- . tion, scientists needed to take a much closer look at the other 98 percent of human DNA.

The past decade of research has pro­duced a cornucopia of surprises, forc­ing evolutionists to rethink their posi­tion on junlt DNA. Yet the opposition among dyed-in-the-wool evolutionists remains fierce, continuing to hinder research into the secrets of the human body and the nature of disease.

A DECADE OF DISCOVERY. In 2003 the ENCODE project (acronym for ENCy-clopedia Of DNA Elements) was launched to begin evaluating the role of the non-protein coding DNA regions of the genome. In 2007 the ENCODE proj­ect released the first series of papers explaining their findings after ana­lyzing just one percent of the human genome. Their initial findings were shocking—”junk” DNA was hot junk; it was very likely functional!

In 20i2, another series of papers was published, and the ENCODE project’ estimated that at least 80 percent of the genome is functional in the sense that it has “specific biochemical activity.” While this is a broad, general term that has stirred much debate, it indicates that researchers still have a lot to learn and understand. Much of the function is believed to be regulatory. In the simplest terms, the non-protein coding parts of the genome (formerly called junk) are telling the genes when to produce their products (the proteins) and a whole lot more.

The goal is to eventually figure out the function of each and every one of the three billion bases of human DNA. ENCODE researcher Tom Gingeras said, “Almost every nucleotide is asso­ciated with a function of some sort or another, and we now know where they are, what binds to them, what their associations are, and more.” Ewan Birney, ENCODE’s Lead Analy­sis Coordinate; said, “It’s likely that 80 percent will go to 100 percent.”4 In light of this evidence, it’s obvious that a more appropriate term for junk DNA is needed! In fact, ENCODE research­ers themselves don’t even use the term junk DNA, but instead refer to these regions as non-coding DNA.

One obvious benefit of the ENCODE findings will likely be disease diagnosis and treatment. For many years scien­tists have known that certain varia­tions in DNA (called single nucleotide -polymorphisms, SNPs) are associated with risks for a disease or with the disease itself. But 90 percent of those variations fall outside of genes (they are in the junk DNA). Up to this point no one really knew how that variation was causing disease.

The ENCODE study found that 60 percent of these variations fall in regions that may affect the activity of genes. For example, the ENCODE study found five variations in patients with Crohn’s disease related to a specific factor that past researchers weren’t even looking at. Of course, translat­ing the lab science into treatments will take time, but it puts scientists one step closer in the battle against dis­ease in this sin-cursed world.

A third phase of the ENCODE proj­ect is now beginning to further refine exactly what all the junk DNA is doing. Ewan Birney stated, “We are the most complex things we know about. It’s not surprising that the manual is huge. I think it’s going to take this century to fill in all the details.”

UNDETERRED NAYSAYERS. Although many scientists were thrilled about the newest ENCODE findings, there has also been opposition. For many evolutionists, the finding that junk DNA has function is inconsistent with an evolutionary worldview. It was assumed to be an evolutionary waste­land of sequences that were discarded as. humans climbed the “tree of life” from a single-celled organism. One popular argument against the idea that junk DNA has function is the so-called “onion test.” Evolutionary biologist, T. Ryan Gregory states, The onion test is a simple real­ity check for anyone who thinks they have come up with a uni­versal   function   for   non-coding [junk] DNA. Whatever your pro­posed function, ask yourself this question: Can I explain why an onion needs about five times more non-coding [junk] DNA for this function than a human? The   common   onion,   Allium   cepa, has a genome fives times as large as the human genome.   The   argument goes that if onions, which are much less complex than humans, have a lot of junk DNA that is not functional, then junk DNA in humans must not be functional either. Other onion spe­cies with smaller amounts of DNA can grow and survive quite well without the large amounts of DNA. So junk DNA in Allium cepa—and by analogy humans—is not functional.

But this is an argument from igno­rance. Do scientists know that this DNA is not necessary for the onion? It’s possible that junk DNA is only neces­sary under certain environmental con­ditions, as onions don’t have the same choices as mobile organisms.

This is yet another example of how evolutionary ideas can inhibit scien­tific discovery. It is rather ironic that creationists are accused of inhibiting scientific discovery because of their supposed “God-did-it-so-there’s-nothing-more-to -study” mentality. In real­ity, the opposite is true. Creationists for many years have argued that junk DNA is not junk.

Once again we see that observa­tional science is consistent with his­torical science based on God’s Word. Scientists have observed, tested, and discovered that “junk” DNA is key to genome function’. This is consistent with an omniscient and omnipotent Creator God who designed and created all living things, including their DNA, during Creation Week approximately 6,000 years ago.

Creationists may look forward to the next installment of papers from the ENCODE project. Hopefully too, the term junk DNA will be discarded as evolutionary debris, and God’s design emphasized, as it always should have been.

Advertisements
Tagged

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: