We’ve been trying to figure out how DNA works since the dawn of time. We can be reasonably certain that people have always looked at one another, or at entire families, and wondered things like, “How is it we all have the exact same gloriously curly hair?” or, “Why do all the members of the family next door run like gazelles when we’re more turtle-like?” When people were thinking these kinds of things, they were thinking about DNA. They just didn’t know it yet.
And it wasn’t just in people. Farmers observed characteristics in livestock, for example, and selectively bred sheep to have gloriously curly and fine wool. They picked and cultivated the sweetest red apples found growing wild, rather than the tart, woody green ones — all decisions rooted in DNA.
We could sense there was something unseen governing inheritance in every living thing around us. A lot of theories were put forward, held up as fact, and then abandoned as the centuries and millennia ticked along (Preformationism, anyone?).
Eventually, these theories were refined into what we call genetics. Coincidentally, the theory of genetic inheritance and DNA as a compound were both described in the mid-1800’s, but they weren’t directly linked to each other for almost another 100 years. Experiments showing that DNA is the molecule responsible for inheritance were done in the 1940’s and 50’s, shortly before the now-famous double helix structure was discovered.
What is DNA?
So what is DNA? And what does it have to do with sprinting and curly hair? Put simply, DNA is