Take out any one cell of human body. Then take out all the DNAs. List out the complete sequence of nucleic acid bases on either strand. This sequence would have well over 3.2 billion characters. The sequence would comprise of 4 letters: A, T, C & G and would look like something like this:
If we type this sequence on Microsoft Word using font size of ’11’ and font ‘Calibari’ with default margin setting as shown in the image below, it turns out that 1 page of this file would contain 3,192 characters.
So how many pages would we need to print out the entire sequence? It turns out that we need around 1 million pages just to print out this sequence! But hey, I didn’t even talk about the size of cell or nucleus or chromosomes. So let’s have a rough idea about that too. The average diameter of cell nucleus which contains all the chromosomes is just about .001 mm and chromosomes use merely a small fraction of nucleus volume. DNA strands are so tightly packed that if we put all the stretched chromosomes end to end, the entire length would be approximately 1 meter!
Human body have around 100 trillion cells, that is 10^14 cells. For the sake of simplicity, let us assume that all these cells have chromosomes inside their nucleus. Now work out this calculation. Genetic information, in the form of sequence of bases of one strand of DNA contained by a single cell needs 1 million pages to be printed, how many pages do we need to print ‘all’ the genetic information possessed by our body? I know you are having an anticipatory idea. Let us put it in another perspective. Suppose you bind 1 million pages to form a book, this book would have 5,00,000 (with both side printing) pages. That means we would have 50 trillion of such books once we are done with this printing. That is the kind of number we don’t encounter in our lives. Though all these trillions of cells have exactly the same genetic information. It is just like every christian has his own copy of Bible.
How about the memory size these ‘e-books’ would consume on your computer? The file shown above is 16 KB file. That means we need 16 (file size of 1 page in KB) * 10^6 (total page for one cell) *10^14 (total cells) KB= 1.6*10^25 KB. That means we would need approximately 1.5*10^19 GB memory.
Or let us just talk about only a cell. The genetic information, if typed as shown above, would need a MS Word file whose size would be approximately 15 GB! Nature didn’t plan on such incredible feats. You’ll be able to appreciate these once you understand that all these kind of things ‘just happened.’
Related link : Read here.