Generally, a genealogical DNA test might use either autosomal STRs or autosomal SNPs. (STR's are Short Tandem Repeats; SNPs are single-nucleotide polymorphisms.) However, testing companies do not currently offer autosomal STRs tests that use enough STR markers for genealogy.
The schema is the Active Directory component that defines all the objects and attributes that the directory service uses to store data. The physical structure of the schema consists of the object definitions. The schema itself is stored in the directory.
The schema defines what kind of information the directory can hold. With Active Directory, a single schema applies to the entire forest; that is, all domain controllers must use the same schema. With ADAM, each stand-alone ADAM instance or ADAM configuration set can have its own schema.