Junk DNA? We Don’t Think So


junk dnaWe are our DNA. It was not a surprise to find that our entire DNA is Functional (“Junk DNA Isn’t Junk, and That Isn’t Really News”). The surprise is in the discovery of what we can do with what we once thought was junk. According to that recent NPR article, “It is a massive control panel that regulates the activity of our genes.” Our genes “would not work” without it. So instead of being junk- they are critical and “control how cells, organs, and other tissues behave.” But we can also now read the markers and mutations on this “panel” and discover much more information than knowing it is just working efficiently for our body. This knowledge is considered a “major medical and scientific breakthrough” (Ibid.). We just have to read it well.

But first, what is DNA exactly? John Wilwol, in his recent NPR article, “A ‘Thumb’ on the Pulse of What Makes Us Human,” quotes Sam Kean, author of the book, The Violinist’s Thumb And Other Lost Tales of Love, War, and Genius, As Written by Our Genetic Code, as saying that DNA is what makes us who we are. Wilwol further quotes Kean to help us understand what DNA is and how it differentiates from genes: “ ‘While DNA is a thing- a chemical that sticks to your fingers, he writes, genes are more conceptual in nature, …“‘like a story with DNA as the language the story is written in.”

So if DNA is a language how are we able to read it? All parts of our genetic code are now readable and meaningful. Marker locations (loci) are spread across one’s entire genome, not confined to one’s male (Y chromosome) or female (mitochondrial) DNA. (This is how sex-linked, haplotype tests that follow one line at a time are analyzed). Different mutations are handed down genetically – different according to the region where one’s ancestors lived.

Because of this new ability to read markers, consumers are now able to buy Autosomal DNA tests that provide a complete analysis of where all one’s ancestors’ ethno-geographic origins – reflecting the entire spectrum of all ancestral lines. Not just one line at a time as in haplotype testing. This is next generation ancestry DNA testing and the wave of the future. Anyone can take an Autosomal DNA test because it does not rely on X or Y chromosomes (women are unable to take the Male Y- linked test and must entice a male in her line, if one is available, to take this test). The future is now in many ways.

What else can you learn from Autosomal DNA testing? Anne Tergesen, in a recent article in the Wall Street Journal,” quotes Megan Molenyak, author of, Hey America, Your Roots Are Showing, as saying that this relatively new test deciphers the amount of DNA shared between those whose common ancestors lived within the last half-dozen or so generations. Tergersen explains it like this, “Y-DNA and mitochondrial DNA can connect people whose common ancestors lived recently or hundreds of years ago. But to find out how closely you are related—and to locate relatives besides those on your direct maternal or paternal lines—you will need an autosomal DNA test.” (Of course, you would both need one to compare) and “in general, the more DNA two people share, the closer their connection”.

But there are even more things on the horizon with Autosomal DNA for the future. Personalized Medicine. According to a recent Smithsonian article, “Fetal Genome Sequenced Without Help From Daddy,” “A fetus’ entire genome can now be sequenced” from the mother alone with a “99.8% accuracy.” How is that possible? It was just “last month clinicians announced that they could sequence a fetus’ entire genome by taking samples from the pregnant mother’s blood and that of the father to be” (“Fetal Genome”). Now they have a “more difficult, but more complete method [that] uses DNA from the pregnant woman and the fetus to map out every last letter of the fetal genome…with the advantage that it can pick up mutations that a fetus has but its parents do not” (Ibid.).  Rob Stein quotes Dr. Alan Guttmacher, director of the National Institute for the Child Health and Human Development in a recent NPR article, “Genome Sequencing For Babies Brings Knowledge and Conflicts,” as saying, “Instead of screening for currently something like 30 conditions, it would allow you to screen for hundreds if not thousands, [of conditions] at birth.  He goes on to say that, “One could imagine a day where knowing someone’s entire genome sequence at birth, you could really begin to think about structuring health care, their dietary choices, their exercise choices…early in life, in a way that would have an impact on truly lifelong health.” Stein says that this gene sequencing could “spot babies that are prone to conditions such as obesity, diabetes, heart attacks or cancer” and that we may soon be “sequencing all babies when they’re born.”  It could be a wonderful tool. But we are not there yet.

According to Rob Stein in another recent NPR article, “Perfection is Skin Deep: Everyone has Flawed Genes,” Scientists have determined we are all more flawed than they thought. “Researchers discovered that normal, healthy people are walking around with a surprisingly large number of mutations in their genes.” Chris Tyler-Smith of the Wellcome Trust Sanger Institute in Cambridge, England and his colleagues analyzed the DNA of 179 people from several countries who volunteered their genetic information to the 1,000 Genomes Project.

 

In a published paper in the American Journal of Human Genetics, the researchers reported that though none of the people whose DNA was studied were sick, the average person has about 400 minor flaws and one or two that could contribute to disease. Tyler-Smith says, “It’s a bit surprising that people should be walking around apparently healthy yet we’re seeing known disease-causing mutations in their genomes,” he says. “But the answer was that these tended to be for mild and very often late-onset conditions. Things like heart disease, an increased risk of disease or developing cancer. On its website, the American Diabetes Association highlights the interaction of genetic and environmental factors: “You inherit a predisposition to the disease then something in your environment triggers it. Genes alone are not enough.”

 

So the problem is not so much with the analytical tool but rather the possibility of over- interpretation. Again, we just have to read it well, with the same critical eye for what is written in us as that which is written by us. And who knows what else we will soon be able to discover from reading our DNA?

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