The Science Behind the Roots Project

The African-American DNA Roots Project has been developed to use specific DNA analysis techniques to attempt to identify unique signature sequences among African-Americans that might link them to particular West African tribes.

This study will determine the genetic patterns present in two types of DNA, known as the Y chromosome DNA (Y DNA) and mitochondrial DNA (mtDNA). These unique genetic elements are passed directly through the paternal and maternal lines, respectively. Each person’s Y DNA or mtDNA comes directly and solely from his or her father or mother, who got it from their father or mother, who got it from their father or mother, and so on into the past. This property makes Y DNA and mtDNA very useful for learning about the past history of human populations because it traces a direct line of paternal and/or maternal descent. Additionally, different paternal and maternal lineages have different genetic signatures in their Y DNAs and mtDNAs, so that all paternal or maternal relatives from a lineage can usually be distinguished from those of other lineages.

Once the Y chromosome and mtDNAs are characterized, they will be compared to reference lineages to identify matches. It should be relatively easy to identify the continent of origin for many mtDNA and Y chromosome sequences. In contrast, there is no guarantee that a match will be found for any particular Y chromosome or mtDNA, and if a match is found, there is no guarantee that it will have geographic significance. However, we anticipate that a small number of mtDNA and Y chromosome sequences will be found only among the members of specific African tribes and in individuals who have a direct line of descent from a member of the tribe.