Genealogical DNA Testing:
The type of genealogical testing technology
used by 23andMe, Ancestry.com, Family Tree DNA, My Heritage
and Living DNA
test less than 0.1% of your genome. Their tests, which
are called genotyping
microarray tests, do not sequence your genes
and do not test your whole genome.
Most use a custom
Illumina OmniExpress SNP (single
nucleotide polymorphism) chip. This chip tests
637,639 autosomal SNPs, 28,892 X chromosome SNPs,
1691 Y chromosome SNPs, and 195 mitochondrial DNA
SNPs.
The number of matches that you will have depends on
the number of people in the company’s database, the
number of people with your ancestral background who
have been tested, and the criteria that the company
sets for what constitutes a match.
