DNA or deoxyribonucleic acid in long, present in almost every cell in your body. It is made up of repetitive units of nucleotides composed of a deoxyribose sugar, a phosphate group, and a nitrogenous base that can be either adenine (A), guanine (G), cytosine (C), or thymine (T).
DNA contains all necessary information to build and maintain an organism. Although there is only around 0.1% difference between your DNA as compared to the stranger sitting next to you, this small variation contributes to significant differences including skin colour, height, IQ, personality, and even disease risk.
SNPs, single nucleotide polymorphisms in long, is the variation of nucleotides at one position in a DNA sequence among individuals. SNPs are one of the major factors that lead to the 0.1% difference among people.
SNPs alter the physical and chemical characteristics of its product, protein. Protein plays a big role in our body. It involves in biological processes such as digesting the eggs you ate this morning, transporting oxygen from your lung to your toes, and coordinating your eyes and your brain so that you can understand this explanation.
SNPs can cause no effect, mild changes to severe consequences. A classic example of defective SNP is sickle cells anaemia. Polymorphism of adenine nucleotide at the haemoglobin beta (HBB) gene results in sickled shape red blood cells that have reduced efficiency in carrying oxygen.