It’s been a rough week so far – been stumbling out of my Thanksgiving food coma. So, it seems like the right time for a light, quick and fun post. Last week I came across a really interesting site from the genetics group at the University of Utah. It is a fantastic graphical comparison from a coffee bean on down to a carbon atom. Go play with it – it’s pretty fun!
The site made me think about size relativity on a cellular scale with respect to the human genome. Within each of our cells is a structure called the nucleus. It’s the structure that contains all of our DNA – some people think of the nucleus as the “brains” of the cell, but I actually think of it more like a hard disk – the nucleus stores all of the cell’s important information. It stores our “code.”
So, here’s where the number fun starts. The nucleus of a human cell is on average 6μm (or 6×10-6 meters) in diameter. VERY small – that’s not a whole lot of space to hold anything. Yet, at a bare minimum the complete human genome is about 20GB (that’s a fairly conservative number – some people estimate the genome at between 50 and 100GB of info). That means that the nucleus stores all of our DNA, in just 137μm3 of volume. That translates to just about 0.18GB in just 1μm3 of nucleus.
Here’s where we can make things a little more interesting. In comparison, if a modern hard drive were to have the same “data density” as a cell’s nucleus, one typical hard drive would be able to store almost 6.9 × 1013 GB of data. That’s the equivalent of all the data on the internet 140 times over. Put another way – if our hard drives had the same “data density” as a cell’s nucleus the typical hard drive would be able to store 140 internets. Thems a lot of tubes!
Those numbers are pretty hard to grasp, I’ll admit that. But, the bottom line is that each of the cells in your body contains at least 20GB worth of information! That’s crazy considering you’re comprised of almost 10 TRILLION cells. I feel like this is one of those “just how big is the universe” type questions, but it’s all completely within the human body.
Even though these numbers are really hard to grasp, it does illustrate to me that the body stores its genetic information in an incredibly efficient and amazing manner. That and our information technology has a long way to go before it matches the efficiency and capacity of the human body. Just a bit of a brain teaser and fun following a holiday weekend!