Every company providing DNA testing has their own database of DNA samples. These are called AIM’s or ancestry informative markers. These markers were derived from the current populations of America, Asia, Europe and Africa. Every database is looking for a pair of genes located on a specific chromosome in a specific position. The way the DNA is evaluated is through the SNP’s or the single nucleotide polymorphisms. The SNP’s are chosen according to the frequency in a specific geographical population. Your SNP’s are compared to the most common SNP’s for the various populations in the company’s reference database. The results are not conclusive because they are based on common genetic variations. The probability for your DNA being from a certain country is based on a comparison between your DNA and the database. If you used a different company, they would have a different database. This means your results would most likely differ. According to studies, the lowest concordance is with individuals of South Asian, East Asian and Hispanic descent.
You might want to stay away from DNA tests if you or any of your close relatives have committed a crime. Although ancestry DNA testing companies don’t typically share database information with law enforcement, consumer DNA tests may result in future identification. For example, FamilyTreeDNA, which has a database of close to a million samples, has agreed to give the FBI limited access to the company's DNA database. This access consists mainly of consumer-level insights, like matches with other members of the FamilyTreeDNA community who have enabled family matching; by law, however, more in-depth investigation requires a subpoena.

AncestryDNA is a cutting edge DNA testing service that utilizes some of the latest autosomal testing technology to revolutionize the way you discover your family history. This service combines advanced DNA science with the world’s largest online family history resource to predict your genetic ethnicity and help you find new family connections. It maps ethnicity going back multiple generations and provides insight into such possibilities as: what region of Europe are my ancestors from, or am I likely to have East Asian heritage? AncestryDNA can also help identify relationships with unknown relatives through a dynamic list of DNA matches
Finally, if you happen to meet a special someone on DNA Romance and want to see what your future child together might look like, there’s BabyGlimpse by HumanCode. Like a very advanced Punnett square, BabyGlimpse compares your and your partner’s DNA to create a profile that examines which traits your offspring might inherit, including things like ancestral DNA, eye color and lactose intolerance.
The most important part of this process is registering your kit before shipping it. All five services require this, and if you don't do it, you won't be able to access your results. This requirement is to protect your privacy—your name won't appear on the kit or the results—and to easily track your kit as it goes through the process. Of course, when you sign up for an account with these services, your identity will be associated with it, but the sample and any reports stored on the service's end will just have a unique barcode.
My own results are eagerly awaited: the whole process takes about 6 weeks. I am somewhat more sceptical having Polish heritage and therefore my contact with relatives might be less likely, however I am waiting eagerly to see whether I have any trace of the Mongol hoards who invaded deep into Europe. I have posted a screenshot of how long the process takes from activation.
Hello…so I am interested in purchasing a few test for myself, my sister and my brother for Christmas. Primary interest is just seeing what our true roots are. Growing up we have been told we are Native American (Nipmuc tribe) and african american with some roots in Jamaica but I would love to see how accurate that all is. Not really looking to get “connected” to any long lost relatives but it would be great to know where in the world we “originate” from when looking into our ancestry. Which test would be the best for these results? Thank you… Read more »

As my dad and I have begun to explore our genealogy over the past seven years or so, we’ve found that our family is largely from Spain, which is no big surprise. Colombians have a wide range of ethnicities, which explains why many Colombians, including my mother, have white or fair skin with blue eyes. My dad also suspects we have German ancestry somewhere back there.

Which is all very well, but do these kits work and deliver the service they promise and what about the wider ethics and implications of home genetic testing? Is it always wise for generally under-informed, under-prepared consumers to meddle in the highly complex, nuanced arena of genetics, risking confusion, complacency or even outright panic and anxiety when confronted with ostensible “bad news” (which may not even be true)?