DNA test companies that use genotyping technology, including 23andMe and Ancestry, allow you to download your raw DNA file. A raw DNA file is usually a text file that contains all the information about your genetic code gleaned from the company’s examination of your DNA. This is comprised of several hundred thousand markers known as SNPs (Single Nucleotide Polymorphisms). Most raw files are organized into five columns: the SNP coded into an rsID number, the chromosome the SNP is located on, the location of the SNP on the chromosome and the two alleles for each SNP.
Alzheimer's disease is characterized by memory loss, cognitive decline, and personality changes. Late-onset Alzheimer's disease is the most common form of Alzheimer's disease, developing after age 65. Many factors, including genetics, can influence a person's chances of developing the condition. This test includes the most common genetic variant associated with late-onset Alzheimer's disease.
Of course, most DNA used by law enforcement in the U.S. does not come from direct-to-consumer DNA tests. The federal government and many states collect DNA samples from suspects of violent crimes after arrest or due to probable cause. These samples are added to the Combined DNA Index System, or CODIS, which is a national database for forensic information.
With a 16-day turnaround, MyHeritage DNA was one of the first companies to send back our test results, but I found the contents of my ancestry report to be a bit off, especially when compared to my geographic ancestry reports from other companies. I was born in Korea and therefore expected at least a little of my Korean heritage to make it onto my ancestry map, as it did with other services, but MyHeritage didn’t report any Korean heritage. 
Then comes the section about serious genetic variants. So far as “counselling” goes, previously, I’d waved away concern for my psychological welfare from the Observer’s science editor (“I’m a former goth,” I said. “My default setting is ‘doomed’”), but it turns out to be quite daunting. It doesn’t help that I initially mistake the full list of potential conditions for my own results, hence (thankfully briefly) thinking that I have higher risk factors for everything going. It makes me wonder – how many other people are going to do that?
I was interested in the ethnicity test provided by African Ancestry because of their claim to be able to place your ancestry in a current African country or region. However after reading multiple reviews, I'm hesitant to spend $300 to find out my ancestors are "West African" or from Sub Sahara Africa. Is there any company whose test can place Ancestry within a specific region of African?
Y-DNA Tests: Y-DNA testing examines the Y chromosome passed only from father to son and can therefore be used to gain a better understanding of your paternal line. This can be a very interesting study for those focused on surname research, especially since the Y chromosome can give information about deep and recent roots. Because only men carry this chromosome women will need to test their father, brother or other male relation to use this test for genealogy purposes. Again, FTDNA is the leader in this type of testing and has a wealth of information, groups and forums to help.