Having given these questions much thought, I thought a good starting point would be to look back and start researching my own family history. When I was young I always thought I was 100% British. My Dad was born in Edgware and my mum in Hampshire. Of course, none of us are truly 100% British and as I got older I learnt that my Dad had Russian great-grandparents on one side and German on the other, and that my great grand-parents on my mother’s side were Greek. So I suppose this is when I started considering how much of my identity was defined by my family history.

Many people who submit their DNA to a direct-to-consumer company also upload their raw information to public databases like GEDmatch, which law enforcement can access. People upload their raw DNA data after taking another test, like those from 23andMe or Ancestry, to several open online DNA databases. Most companies do not release database information to law enforcement. However, a recent study found that, using publicly available data, it's possible to identify up to 60 percent of Americans with European heritage via third-cousin-or-closer DNA.

Thank you for this webpage! It is very insightful. I wish I had found it earlier. I did the DNA test through 23andMe, a doctor’s office already had me DNA checked for health (Medical DNA Labs in Tampa, Florida). I am wanting to know more about my genealogy and the report I received from 23andMe shows most concentration from the British Isles so now I will probably do ancestry and maybe Living DNA. You did a fine job in explaining everything, again thanks!

This is a large amount of data not being used by services testing DNA. There are millions of SNP’s contained in your DNA. This type of testing only looks at specific variations. This requires between 100 and 300 AIM’s. This is a small fraction of the SNP’s differentiating DNA. This means if your test stated you are fifty percent European, it means only half of your SNP’s appear to be European. Another issue is certain markers used for ancestry information for any given test are only derived from either your Y chromosomes or your paternal line or your mitochondrial DNA or maternal line. When these markers are used, your test will be less accurate. Another flaw is the DNA testing services are obtaining DNA from the current populations in specific regions. This makes unsubstantiated conclusions that the people living in these areas hundreds of thousands of years in the past have had the same DNA for all these years.
There are mixed reactions to the use of ancestry DNA databases in criminal cases. On one hand, the rise of readily-available DNA information for millions of people has led to the arrests of several suspects related to long-cold cases, including the arrest of the Golden State Killer. On the other hand, law enforcement accessing private databases of genetic information from consumers raises several questions regarding privacy and ethical issues.
The spit is for one of the home genetic-testing kits I’m sampling. A growing number of these kits (brands such as 23andMe, DNAFit, Thriva, MyHeritage DNA, and Orig3n) promise to unlock the mystery of your genomes, variously explaining everything from ancestry, residual Neanderthal variants, “bioinformatics” for fitness, weight loss and skincare, to more random genetic predispositions, denoting, say, the dimensions of your earlobes or the consistency of your earwax.