Full text of How You Know You’re in Love: Epigenetics, Stress & Gender Identity by Karissa Sanbonmatsu at TEDxABQ conference.
Listen to the MP3 Audio here: How You Know You’re in Love_ Epigenetics, Stress & Gender Identity _ Karissa Sanbonmatsu _ TEDxABQ
I love you.
When you are in a relationship, when do you say, “I love you,” for the first time? How do you know you are in love? When do you define the relationship? And when do you make it ‘Facebook official’?
We all know the symptoms of love: the butterflies in your stomach, your hands getting clammy, so nervous, you are terrified, but you cannot wait for more.
There’s a lot going on when you fall in love. You thought it was just a bunch of heartache and money. Your brain goes through all kinds of changes. It gets flooded with oxytocin, the love chemical. Falling in love is physiological.
On the other hand, since the time you could walk, you’ve heard stories about love from everyone. Is the ability to fall in love genetically programmed or were you conditioned to fall in love? Is it nature or is it nurture? We don’t know.
What exactly do we mean by “Nature vs. Nurture”?
By Nature we mean things that are genetically programmed, passed down from generation to generation, apart from a fluke mutation once in a while. By Nurture we mean things that are learned, or a product of your environment, like riding a bike, or maybe staying in the sun too long and getting skin cancer.
Now how about the ability to deal with stress? Is that genetically programmed, or a product of your environment? How about gender identity? Nature or Nurture?
How about the ability to annoy people? Don’t you just want to ask that annoying person at work: “Were you genetically programmed to be that way?”
“Or do you actually practice that in front of the mirror all day?”
Well some traits are not nature and not nurture but something different all together: epigenetic.
Epigenetics literally means a layer above your genetics. If your genetics is the hardware, your epigenetics is the software, or the operating system. Your epigenetics allows the environment to change your DNA.
The most famous example of epigenetics is the response to stress. A group in Montreal used rats to go after the specific question: “If you are an attentive mom, does that affect the DNA of your children?” They looked at two populations of rats. In population number 1, the mothers were very nurturing, licking and grooming their pups. These baby rats actually have the royal treatment. Mom’s cuddling them all the time, tying their shoes, driving them to soccer practice every day. These baby rats had it made. Well, they looked at the DNA of these baby rats, and the DNA looked fine.
In population number 2, these mothers were not very nurturing. No licking, no grooming, no cuddling. Not very attentive. Well, they looked at the DNA of these baby rats and they found strange marks on that DNA, and those marks were positioned precisely at the stress response gene. In fact, these baby rats couldn’t deal with any stress at all. And that behavior persisted for their whole lifetime.
Well, for kicks, they decided to look at the grandkids’ DNA. And the grandkids’ stress response gene was turned off too.
How could that possibly be? How can a mother nurturing her pups change their DNA?
Well let’s think about what DNA is. DNA is a molecule that’s very thin and very long. There is enough DNA in your body to wrap around the Earth 2.5 million times.
So how can all that DNA be squeezed into your body in such an organized way to control everything? Your DNA is threaded around tiny, microscopic spools, trillions and trillions of these spools.
Here we can see DNA in all its glory, atom for atom. It’s wrapped around molecular spools, called histones, in blue. At first, the stress response is turned off. But when our baby rats are being hugged and cuddled, serotonin is released in their brains. Serotonin turns on a light switch, called lysine number 4. This is chemically modified, or acylated, triggering the spools to unwind, unwrapping the DNA, exposing the stress response part to the cell. So our baby rats are happy and healthy.
You can think of it like a garden hose. Imagine a garden hose a mile long, here in this theater, floating in the air. Do you know those garden hose spools, the plastic ones, to store the garden hose? Imagine thousands of those spools winding and unwinding, turning genes on and off with exquisite precision. Somehow, these spools have special powers. They know what is happening all around the cell. They can turn the genes on and off at just the right times, at just the right moments. They are so exquisite, they can take an egg cell to an embryo to a newborn baby.