When it comes to DNA testing, genealogy and medical testing are not the same. Both sciences are advancing all the time, but their approach and what the scientists are looking for are vastly different. For this reason, before you have your DNA tested, be sure you know why you want this procedure done.
The testing of a person’s DNA for genealogy purposes involves the identification of nucleotides and where they are located on the sample DNA strand. This identification process, when looked at as a whole, can tell the examiner many things about the samples genetic ancestral past.
In the Y-DNA samples that are examined, the order and composition of the identified markers is how it is determined what family line the sample comes from. This DNA strand is passed on from father to son and is a continuous marker of the family lineage. A scientist can compare two different samples and can determine if they are ancestrally linked genetically.
This same type of matching up of like samples can be done for the female DNA strand or the mtDNA. By identifying matching sequences in the sample, an ancestral match can be found.
Neither of these tests will give a person any medical information. The reason is because of what the scientists are looking for. There is some association between haplogroupgs and diseases or certain characteristics like longevity of life. This is only because further testing has already been completed. This includes the association of particular markers that are missing or present from a DNA strand and disease.
For this reason, DNA testing, genealogy, and medical testing are different and the results from one cannot be used for the other, in most cases.