Mutations of DNA building blocks

 
When new cells form, the complete genetic information is copied so that the daughter cells are also equipped with the complete information. The copying procedure is relatively accurate, but it does happen occasionally that the DNA building blocks are not copied exactly according to the template. Thus, there can be alterations in individual DNA building blocks that can in turn be passed on. Variants of individual DNA building blocks are also known as SNPs (single nucleotide polymorphisms).
 
The human genome contains about 10 million SNPs, some of which are responsible, for example, for differences in our outward appearance or how we respond to medications. Many SNPs do not lead to any obvious changes or have effects that have not yet been investigated.
 
SNPs are both mainsprings as well as witnesses of evolution. They can be used in relatedness analysis, both between individuals as well as between entire populations.