The ad for Ancestry.com's DNA testing company is not only selling me a service, it is selling me an ideology: Submitting my DNA, it said, you would "answer, once and for all, what it is that makes you, you." Really? DNA makes me me? This is pseudo-scientific garbage. DNA is the score, not the performance. Who we are - as opposed to what we are - depends on upbringing, education, what's in the environment, opportunities for physical and intellectual growth, and just plain luck.
Twins start off with the same DNA, but they can become be quite different. I was present when Stephen J. Gould filmed a television broadcast in front of the death cast of Eng and Chang Bunker, the "original" Siamese twins. Eng and Chang were very different people - Chang became an aggressive fellow who liked strong drink, while the Eng was a mild-mannered teetotaler. And these two businessmen shared not only a liver and a circulatory system; they shared their genomes (they were identical twins) and, by force, they had to share the same environment. What makes us "us" is a very complex mixture of genes, environment, and experience.
But we hear over and over again, "DNA makes us who we are." We are even told this by our car ads! We hear that "superior handling is in the DNA of every German sport coupe"! The "red-blooded attitude" of the Jeep Compass is "genetically engineered" to take that DNA places no one has seen before. A decade ago, the ad for the midsized Hummer had the tagline, "Same DNA. Smaller Chromosomes." In other words, the size may be smaller, but the essence hasn't changed. Biologically, this makes no sense. DNA had become our essence, perhaps even our soul.
I'm not saying anything new to sociologists. They have known this ever since Susan Lindee and Dorothy Nelkin wrote DNA Mystique exactly 20 years ago. These researchers warned us that we were creating "sacred DNA."
And they were correct. We are starting to believe our advertising. Governor Michael Huckabee claims "we clearly know that that baby inside the mother's womb is a person at the moment of conception. The reason we know that it is is because of the DNA schedule that we now have clear scientific evidence on." However, there's no such schedule. Carly Fiorina says, "Science is on our side. It shows ... the DNA on the day that we die is the same DNA we had as a zygote." Actually, it isn't.
There's no such thing as a "DNA schedule," and the DNA that we die with is actually different from the DNA with we come into the world. Identical twins start off with the same DNA, but as they get older, their DNAs diverge. That is because DNA is modified by experience and by chance.
The science of epigenetics has told us this over the past twenty years. We can see the effects of environment on the DNA of laboratory animals. The DNA of genetically identical rats, for instance, is altered by whether or not the mother rat gives it attention during the first week of its life. Certain genes become methylated (having small organic molecules attached to them), and the result is a marked change in anxious and sexual behaviors. In genetically identical mice, DNA is altered by chemicals (including food) that the mouse experiences while in the uterus. And this exposure, too, can have both physical and behavioral consequences.
DNA is altered by experience, and what we receive at fertilization does not predict who we will be. We shouldn't believe our advertising. DNA a chemical. It is not our "essence." It is certainly not our soul. Fertilization is when we get our DNA. This DNA will help build our hearts and guts. It will make sure our eyes are only in our heads and not in our butts. And it constructs a brain that can learn and change, a brain that allows us, as geneticist Barton Childs noted, "to escape the tyranny of our genes."
DNA does not tell us who we will become. Republican presidential candidates and anti-abortion activists can often be seen bowing to an image of sacred DNA, an idol reinforced by our advertising, not by our science.