As this test traces the paternal line with no influence from mothers, instead of an ethnic breakdown, it provides an ancestral migration route of the genetic population of your paternal line. Each specific genetic population is referred to as a haplogroup and can provide deep anthropological information about the story of mankind as well as help refine your genealogical search. With a Y-DNA test you will see a visual representation of this journey, as shown below:
In addition to providing this deep ancestral migratory route, a Y-DNA test also provides a list of people in our database who share with you a common direct paternal (your father, father’s father, father’s father’s father, etc.) ancestor within the past 25 generations. If a person relates to you through a father’s father’s mother’s line, Y-DNA will not connect you to them. As surnames are traditionally passed down the direct paternal line, Y-DNA testing is particularly useful in surname studies to see how all living people of a certain surname are genetically related.
There are different levels of Y-DNA matches available. Picture Y-DNA as a puzzle with 111 pieces to it. Whatever level of Y-DNA you have, it compares that number of puzzle pieces, or markers, to another person’s to see how many markers you have in common. The number of markers you do not match with another person is called a genetic distance. Generally speaking, the higher the genetic distance, the more distantly related that person is to you. The more markers you test for, the more complete a picture of the puzzle you look at, and the more accurate the genetic distance is. In addition, higher level testing helps refine your matches to those most closely related to you. In the example below, this person started at a 37 marker level and later upgraded to a 67 marker level. His matches were narrowed from 76 to the 24 closest matches at this higher level. Whatever level of test you get, you can always upgrade to a higher level for the difference in price between the levels.