ABOUT DNA TESTING
There are several things that one should know before jumping off the deep end in having a DNA test. In general, such tests are almost useless when it comes to finding out if you are related to some far distant possible relative.
First we must understand that unless that possible relative has been dug up and DNA tested, it is unproven unless there is a proven relative who has been DNA tested to prove the line. The DNA from the not-so-distant relative [if proven] will suffice but that relative has to be a definite proven relation to your distant forebear.
Please remember that some of these DNA test companies will have ulterior motives for collecting DNA samples be it financial, Government "big brother" collections, Law enforcement, CIA, FBI and the related services in other countries.I have noticed that in some cases, that DNA companies are stating that my line is related to William The Conqueror via a forebear who was cousin to that king. 
How can this be stated when the DNA from both my forebear and the conqueror has not been taken. Sure there are proven relatives to the conqueror who are alive and DNA could be taken from them but they are not of my family line so you will note that it is best to be sure of what you are doing when taking DNA tests. Mostly you will find out if you are related to another living person but most DNA seekers want to go back in time, not hang around with distant relatives who are living today.
Yes they can tell you if you have African blood or if you are Indian or European, if you are white or Asian, South American Indian or Australian Aborigine. Once you have submitted your DNA, or your children have submitted DNA to these companies, that material will always lead back to you.