Onwards and upwards with DNA

It occurred to me that the surprisingly long strings of DNA each and every one of us has in every cell of our bodies must have started out as an infinitely short one. I don’t mean in your body or mine, I mean many, many millions of years ago, when uncountable numbers of lightning strikes stabbed into a thick ‘soup’ of chemicals, lying in the hollows of a landscape filled with nothing but igneous rock. The crucial inanimate mixture of chemicals, coupled with the lightning bolts, somehow made the chemicals animate, and life on earth had started, as single celled plants, similar to what we call diatoms today! Obviously, I’ve made up this scenario; I have no more idea than anyone on earth as to how life actually started here, but my guess is that it might have been something like this.

The resulting life form may only have grown to a few combined cells, with no real structure, just a quivering blob, but with a vital, short piece of DNA in each one, providing it with the first important instructions for future growth. Maybe this tiny blob was then able to absorb some of the very soup it had been formed in, so that it gained in strength, until each of the few cells that comprised it, suddenly split and the blob was twice as big as it was before! This could have gone on for several million years, until the blob had developed into some sort of shape, perhaps like a spirogyra or something similar, and all the while its vital DNA spiral was growing in length, as more and more detailed instructions were added, generation after generation.

At the same time I would visualise similar happenings, in tiny puddles, all over the young world, with life springing up everywhere, many of them with DNA messages that were radically different to others, so that the lifeline of each was different. Many millions of such occasions would likely not have worked at all, for one reason or another and so they died, while others succeeded, beginning the long, long pathway we know as evolution! It has taken billions of years for DNA to progress from that tiny stub, perhaps created by the flash of lightning, through numerous mutations, caused by the necessities of an ever changing environment, to the terrifyingly sophisticated molecules of the stuff we each have today.

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DNA (short for deoxyribonucleic acid) is essentially just four chemicals, Adenine (A), Cytosine (C), Thymine (T), and Guanine (G). These base chemicals are apparently combined into pairs, making up the rungs of the DNA ladder, a double helix, for ever wrapping itself around itself, being added to and changed in every new generation. Deceptively simple, but one of the most powerful and wonderful chemical combinations on earth, and every living thing contains it, animal or vegetable.

Today, your DNA is supposedly about 4-feet long and there is a strip of it in every cell of your body. Seems unbelievable I know, but think of all the material you can now store on a 16GB memory card about the size of a ten cent coin, and you begin to realise what a lot of material can be stored in a very small space.

I’m actually writing about things here just for the fun of it, and I would be the first to admit I have little actual knowledge of them, apart from what I have read, or seen on the TV. So I’m hoping that someone much cleverer than me can give us a better understanding of how life stared and how we work – surely the most interesting subject for discussion in the world!

 

Have you ever thought about your DNA? What fascinates you about it?