The way that humans work is that they are multicellular organisms. Each cell works together to create the entire organism. Cells reproduce on a very small scale and need to have DNA to copy in order to reproduce. It isn't feasible to imagine a single repository of DNA for all of the trillions (yup, trillions) of cells in the body to use.
The fact that there are only 4 different nucleotides on DNA isn't restricting to what it can encompass in the information on it. The computer that you are using to type this question only uses a binary system of markers. Ones and zeros, and it can display almost anything that you want it to.
I looked into it because I was just bored.. But DNA has approx. 3 billion (3 x 109) base pairs. So that would be eqivalent to.. Well I don't exactly know how to convert from base 2 to base 4... But I'd imagine that would be somewhere along the lines of at least 2 gigabytes of data. So if you can imagine the amount of data a computer might store in 2 gigabytes of space you'd understand the range that DNA might be able to represent. (approx. 20 yards of books on a shelf.. 1,000 mp3s.. You know)
The fact that there are only 4 different nucleotides on DNA isn't restricting to what it can encompass in the information on it. The computer that you are using to type this question only uses a binary system of markers. Ones and zeros, and it can display almost anything that you want it to.
I looked into it because I was just bored.. But DNA has approx. 3 billion (3 x 109) base pairs. So that would be eqivalent to.. Well I don't exactly know how to convert from base 2 to base 4... But I'd imagine that would be somewhere along the lines of at least 2 gigabytes of data. So if you can imagine the amount of data a computer might store in 2 gigabytes of space you'd understand the range that DNA might be able to represent. (approx. 20 yards of books on a shelf.. 1,000 mp3s.. You know)