Posts Tagged ‘Medicine’

OK, I just learned something that a lot of biologists knew twenty years ago. That’s what I get for watching too many superficial news programs (you know which ones) and not enough of programs on PBS, like NOVA. I recently saw a NOVA episode called “Ghost in Your Genes” and I highly recommend it to everyone, if you haven’t already seen it. The principle idea of the show is this: your DNA is not your destiny. How can that be, I thought. Isn’t DNA the roadmap of our bodies? Well yes, but there is something else besides the DNA in the human genome you’ve all heard about. It’s something called the epigenome, and that makes all the difference in the world.

It turns out that the study of the epigenome and epigenetics is pretty much the hottest thing in biotech today. Who knew? Your genome (the DNA you were born with) and your epigenome interact with each other and the result of their interaction is the DNA you wind up with at any moment in time. The epigenome acts as a sort of gas pedal and brake system for each of your genes, and it is your genes that give you not only the color of your eyes, but every other feature of your body, and maybe your mind too. And those features can change, like when someone who is healthy develops cancer or when a normal child becomes autistic. It looks more and more like a lot of these changes are due to the accelerator/brake pedal action of the epigenome that is active throughout our lives.

If that isn’t amazing enough for you, then think about this: the epigenome’s activity is affected by the environment! It appears that exposure to certain toxins, like cigarette smoke or pesticides, can change the epigenome, which then instructs the DNA to change in your genome and the next thing you know, you have cancer. The epigenome can even be activated by psychological stress. You’ll have to watch NOVA to get all the details, but there is no doubt that this is an amazing discovery that will effect everyone’s healthcare in years to come. However, something else struck me about the epigenome’s activity that the NOVA program didn’t cover. I believe that the epigenome might be the key to explaining evolution.

Ever since Darwin, evolution has been described as adaptation to the environment. Up until now, evolutionists have explained its mechanism as “natural selection”. The idea is that nature makes random mutations in organisms, and some of these work successfully and some don’t. Organisms that receive the good mutation become successful and climb higher up the food chain, while the unlucky recipients of the funky mutations become dinner. The existence of the epigenome presents us with a possible alternative explanation that I have long suspected must exist, an agent of adaptation other than random mutations. By using the brake/gas pedal action of the epigenome, our genome has the capability of responding and adapting to changes in our environment. These successful adaptations are then passed down to succeeding generations. However, sometimes the epigenome makes a mistake and presses the gas instead of the brake (hey, it’s not exactly a HAL 9000 computer, you know). When that happens we get adaptations that don’t really work all that well. Sometimes they actually backfire. We call those diseases.

You have undoubtedly heard about the debate between creationists, who tend to base their arguments on the Bible, and deny the existence of evolution and the evolutionists, whose Bible is the works of Charles Darwin. The real issue here is this: at its core, is the universe deterministic or is a random process. If you choose “deterministic” you have an argument for the existence of God, and if you choose “random process” you have an argument against the existence of God. (It’s sort the same argument that physicists have about quantum theory.) The action of the epigenome, as an agent of adaptation, may serve to sweep away much of the argument. The working of epigenome might explain how man has evolved from the apes, but the creationists could embrace this by saying that the epigenome was long ago included in our biological tool kit by a Creator. Wonderful! Argument over, right? Maybe not. That only pushes the argument back to whether the epigenome was created, or did it evolve by random chance. I think I’ll leave the discussion of origin of the epigenome to others for today. It is enough for me to think that this epigenome might be the smoking gun I have always thought there had to be: nature’s agent of evolutionary change. That is amazing. (By the way, that is not the contention of the NOVA program; that is just my own thought.)

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