Carl Zimmer received his genome in the mail.

And this wasn’t the sort of summary assessment that you might imagine (via a service like 23andMe). This was all of his genetic information. All 3 billion pairs of it. In fact, it was so much information that it came on a hard drive.

Zimmer, a science writer and columnist at the New York Times, believes he’s the first journalist to get his whole genome sequenced. But unless you’re a scientist, there’s not a lot you can learn from a huge sequence of A’s, C’s, G’s, and T’s. So, Zimmer went to some of the foremost experts in modern genomics to see what his genome could tell him about himself.

Here are three things he learned:

His genes make it more likely for him to be overweight:

With 3 billion pairs, there’s lots of mutations and variations. Some of these can be a bit unhelpful:

“I have a mutation, which is relatively uncommon, which is a very strong factor for weight. I have copies of this variant which means that, on average, people with this variant are about seven pounds heavier than other people...it turns out that there’s basically a genetic switch in our fat cells that switches these cells from either burning up energy as heat or storing away as fat. In most people, it can flick back and forth in a useful way - in my case, my switch is stuck.”

He has a mutation that’s actually protective:

There are also mutations and genetic variants that make people less likely to get illnesses:

“Protective variants [are] kind of a new thing for geneticists; they’re putting together a list of these variants that dramatically lower your risk of getting all these diseases. There aren’t many that are strongly confirmed, but I turned out to have one of these, which was pretty cool… I’m protected against certain kinds of auto-immune diseases where your immune system basically goes after yourself. One of these is Crohn’s disease.”

When it comes to genomics and understanding our genes, we’re just getting started:

Finding out what illnesses you’re susceptible to, learning what specific variations your genome has, it’s all interesting. But the field is still in its infancy. There’s still a lot that scientists are learning about:

“I like to think of it as astronomy in the 1700s… it was a science, people were discovering things like comets and planets, but the tools that they had to find those things were pretty crude.”

In 20 or 30 years, Zimmer thinks that sequencing your genome might be as common as getting a blood test.