All genetic code DNA (deoxyribonuclueic acid) is this length of just four chemical 

letters, or bases: adenine (A), thymine (T), cytosine (C) and guanine (G). These pair 

up, A with T and C with G. The human genome has between 2.8 and 3.5 billion base 

pairs. 

The 2m-long string of DNA found in nearly every human cell contains the instructions 

for every physical aspect of your body.

Genes Genes As little as 3% of the total genome is made of genes - the rest is 

meaningless "junk". 

Genes are special sequences of hundreds or thousands of base pairs that provide the

templates for all the proteins which the body needs.

Every human has 23 pairs of chromosomes, one set from each parent.

Nearly every cell in the body contains the full DNA code for producing another 

 human thereby making cloning possible.