So you know DNA is the abbreviation for deoxyribonucleic acid, the molecules that contain the genetic code for pretty much all living things as we understand them. Your DNA is what makes you who you are, with your eye color and hair color and nose shape and everything else. But just how much do you know about DNA in general? It's fascinating stuff, and definitely worth learning more about.
You've Got Some Neanderthal in You
Scientists are always looking back to where we came from in an effort to help us better understand where we're going, and genetics is playing a great role in this because we can sequence our DNA and get a bit of a glimpse at what ancient humanity went through, a long time ago. Fun! And one of the things they've learned is that ancient man was a bit of a player.
Evidence suggests that a long, long time ago, let's say more than 30,000 years ago, humans weren't the only hominids roaming the earth. You've probably heard of Neanderthals for example, they weren't an early form of us, they were a separate but very similar species. And our ancestors intermingled. And not just with Neanderthals, also with a group called Denisovans, who lived around what is now Siberia and split from what would become Neanderthals 300,000 years ago. And if that's not enough, we seem to have also included a 4th species that had never been identified before.
Your DNA is Long, Super Long
DNA exists in your cells in a double helix structure. It's often depicted in drawings as two intertwined strands with little steps between them, like rungs on a curling ladder. Realistically, those things are microscopic and about two and a half microns across which is very small, obviously. So how many of these little, microscopic strands do you have inside you, anyway?
If you uncoiled a strand of your DNA, you'd find an average size of about 5cm. That's pretty small over all. But then if you consider that your body contains over 37 trillion cells in total, if you took out all the strands of DNA and uncurled them, then laid them end to end, you'd be able to get from the sun all the way to Earth 93 million miles away. And then you could go back, and then back again. In fact, you could make 70 round trips from the sun to Earth on your unfurled DNA strands.
Some of Your DNA is Viral
A lot of the genetic makeup of modern humanity can be attributed to retroviruses from our ancestors. As a species we've picked up various bugs over the years that have altered and mutated who we are and how we came to be that way. And surprisingly, that's all still very much a part of us. Right at this very moment, about 8% of the human genome is viral.
As researchers continue to piece together the puzzle of what makes up a human, they've found numerous bits of viral DNA mixed in, some of it likely stretching back through our ancestry over 670,000 years. These are likely the things that carried over as humans evolved from less advanced life forms. Many of these viral components are genetic sequences that may influence how diseases develop and yet other parts may be actually intact viruses that could be reactivated if someone were so inclined, giving insight into the kind of viruses that may have plagued mankind thousands and thousands of years ago.
Your DNA is the Ultimate Storage Unit
If you were in the market for a new computer today, and wanted to get one with some exceptional memory, you could buy one with a 1 terabyte hard drive. That one terabyte would be enough memory to store about 500 hours worth of film, or 200,000 song files, which is a good chunk of information. That's what a computer can do these days. Pay enough, you can even get a 2 terabytes harddrive. Not too shabby.
In the future, it's possible we can use DNA to store data, as essentially that's all DNA does now. Scientists have already used DNA to store and then retrieve files like a full computer operating system, a 1895 French film, an Amazon gift card, a computer virus and more. The reason this is impressive is because DNA is a very efficient storage medium. One gram of DNA can store 215 petabytes, and each petabyte is 1024 terabytes, which is 220,160 terabytes, or 44,032,000,000 songs. A few of those are probably going to be doubles.
The other advantage to DNA is that it has an exceptional shelf life. Digital store media tends to grow old relatively fast. DNA stays good for over 100 years and you don't have to worry about it being upgraded like VHS tapes to DVDs to digital media, we're probably going to be keeping DNA around forever.
Your DNA Has a Long Lifespan, But Not Science Fiction Long
Jurassic World 2 is coming soon, making it the 5th film in the popular franchise and keeping alive everyone's hope that one day we can, for real, be terrorized by monsters of science that should have stopped existing 65 million years ago or more. Dare to dream.
Alas, it looks like Jurassic Park will have to stay a dream as well because, whether or not you find a mosquito caught in amber, DNA has a shelf life. A team of paleogeneticists has studied ancient samples and determined that DNA has a half life of about 521 years, which means in 521 years half of the viable DNA in a sample will have decayed. Now different things can affect this like temperature, bacteria and if water is present, but under ideal conditions – DNA preserved in bone at -5 Celsius for instance – every single bond in the DNA would be destroyed after 6.8 million years. It would be effectively useless after only 1.5 million years. And sure, that's a long time, but it means dinosaurs are officially off the table.
You May Share Some with King Tut
When you breed dogs, or horses, or any animal really, what tends to happen is you have one prize-winning stud who ends up siring a number of litters. Eventually you get a lot of little animals running around, all with the same father. And if some of those become champions, the lineage continues until eventually you can have relatives all over the globe from this one desirable bloodline. Now imagine what happens if a human thinks he's a stud on that scale.
As it happens, there is evidence that a relative of a very famous Egyptian King, you might know him as Tut, but the full name was Tutankhamun, was that sort of man. More than 50 percent of all men in Western Europe belong to a genetic profile group, known by the very snazzy name of haplogroup R1b1a2, to which King Tut also belongs, meaning that they share a common ancestor. So half of Europe is part King Tut and, if you have any European ancestry, you have a 50/50 shot of sharing that DNA.