Article in Wikipedia on Genetic Genealogy

Genetic genealogy is the application of genetics to traditional genealogy. It involves comparing the DNA of one individual to that of others, thereby scientifically determining the person or group to which an individual is most closely biologically related. A close genetic relationship entails a shared ancestry, which may or may not be on record. Therefore, genetic genealogy gives genealogists the means to check or supplement the historical record with information from genetic data...