All the information needed to create life is encoded in this molecule - DNA.
Packaged in tightly coiled structures called chromosomes, it's stored in the nucleus of all our cells.
DNA is what makes each living thing different.
It determines our physical and personality traits.
The function of our DNA is to instruct the cell to make specific proteins.
And, what's more, it can replicate itself, so that identical copies are passed on when cells divide.
Both of these functions are only possible because of the unique shape of DNA.
A double helix.
On the inside of the spiral are four molecules: adenine, thymine, cytosine and guanine.
These are bases, better known as their letters: A, T, C, G.
A, T, C, G
The sequence of these bases varies in every species and in every individual living thing.
And, to ensure that this unique sequence is passed on when cells divide, the A T C G bases are designed to pair up in a very specific way.
A always pairs with T. And C always pairs with G.
So, when the strands split apart, the open helix contains all the information to make identical new strands.
This simple rule is the key to how DNA can be passed on from cell to cell.
DNA contains the blueprints to construct proteins in our cells, which are unique to each of us.
DNA strands truly are the threads of life.