Deoxyribonucleic acid, or DNA, occurs when a molecule has the instruction for an organism to develop, live and reproduce. Under microscope DNA is like a twin chain that coil around each other inform of helix. We have 4 types of DNA in existence now namely Adenine (A), Cystosine (C), Guanine (G) and Thymine (T). Adenine combines with Thymine while Cystosine combines with Guanine to form A-T base pairs and C-G base pairs respectively.
We have 3 types of DNA test so far known for now. These are autosomal and X-DNA, Y-DNA and mtDNA. When test are carried, the autosomal takes care of chromosomes 1-22 and X. The Y-DNA test takes care of Y chromosomes which is from father to son and normally is responsible for paternity test especially for a male children.