Is it possible to know what a person looks like from their DNA?

What a cool question! I never thought of something like this even though I probably should have. I would love to see what Genghis Khan or a Neanderthal really looked like.

If DNA is really the blueprint or recipe for making you, it sure seems like it should be possible to create a picture from it. But it probably isn’t. At least for now, our understanding of our genes just isn’t advanced enough to be able to paint a picture of who we are. Besides, our DNA also couldn’t tell us what the environment has done to how we look.

To really generate a photograph from our DNA, we would need to have an understanding of our genes that we just don't have right now. We can’t even look at someone’s DNA and tell what color eyes or hair (except maybe red) they will have.

But let’s say we gained a deep understanding of our genes and how they interact with one another – could we create a picture of someone?

One thing is for sure; we could not create a picture of you as you are now. The instructions in DNA really are a recipe for making you. What looking at someone’s DNA can't necessarily do is tell us about how the environment affected the instructions.

How we look and who we are is more than our DNA. A simple thing like how much protein someone has while growing up will affect how tall he or she is as an adult, for example. There are probably other factors like what we ate, where we lived or what we did while in the womb and growing up that might affect the way we look too.

Maybe our DNA could tell us what we'd look like if we’d grown up in a vacuum. Even then I’m not sure.

Lots of things happen in our cells that are not necessarily the result of our DNA. Our genes tell us what to make, the environment can affect how much of something a gene makes.

For example, in a male, all the instructions for becoming a male are in the DNA. However, without testosterone, they won’t get turned on enough to turn a boy into a man (or for that matter, a fetus into a boy).

Testosterone is turned on early in development and then again, at puberty. Without this switch to turn on a bunch of genes, maleness just doesn't happen. Sort of like turning on the oven when you’re baking cookies – if the oven isn’t on, the cookie dough doesn’t turn into cookies even if all the ingredients are there.

Of course, this doesn’t mean we can't learn a few interesting things about how some long dead folks looked. For example, a study being done on German fossils showed that red hair was pretty uncommon 3000 years ago. That is all we know so far because red hair is the only trait we can easily screen for right now.

Well, I hope this answered your question. As you can see, we probably won’t be able to sketch any portraits of people from their DNA any time soon. But we may learn interesting facts about how our ancestors may have looked.