I used AncestryDNA for my genetic testing. To have your DNA tested, you send a saliva sample to their labs and results are posted several weeks later. They test your DNA using microarray-based autosomal DNA testing. A microarray is basically a grid of many known DNA segments which then are used to test and map out the DNA sample in question. The microarray used by Ancestry surveys your DNA at 700,000 locations to help find your heritage.
AncestryDNA has an extremely large database not only for DNA testing, but of public records. Here Ancestry can help you create a family tree by using things like U.S. Census records and marriage certificates to link your ancestors. This service can tell you about generations of ancestors, showing you what they did, where they lived and much more. You can start by simply putting you parents and grandparents names into a tree that you create. By adding their name, birth/death dates and birth place, Ancestry will search its database for records of these family members and provide you with a “hint”. By using the hints that Ancestry finds for you, it can help you find older generations like great grandparents. You may also add a family member to your tree that is on someone else’s tree and then you can be linked to their tree which will show much more family members. Using the resource Promethease, I was able to take the raw genomic DNA provided by Ancestry and get a report of what my DNA indicates. Promethease uses my DNA genotypes and compares it with findings that are cited from scientific studies in the website SNPedia.