Pedigrees based on genetic markers can reveal relationships not detectable in genealogies based only on names, written records, or oral traditions. There may be a number of individuals named John Smith, but a genetic identification is unique and can even discriminate between closely related individuals or those sharing the same name. There is not another individual that has ever lived on the earth or that will ever live that has the same genetic identification. In order to reconstruct molecular genealogies it is necessary to utilize known biological relationships and correlate this information with the transmission of genetic markers through time.
All persons receive genetic material from their biological parents.
This fundamental principle of genetic transmission means it is possible to determine the origin of genes based on common ancestry and known modes of inheritance. Because this process is repeated every generation all individuals carry within their DNA a record of who they are and how they are related to all of the other people on the earth. Additionally, different regions of DNA have the ability to identify individuals, link them to immediate family groups, extended family, tribal or clan affiliations and larger populations. In order to determine the degree of relationship between individuals it is necessary to identify those genes, or markers, that are identical due to shared ancestry. There are several ways that this might be accomplished.