A Paternal Ancestry Signature report is produced by analyzing 24 different locations on your Y-chromosome. The fascinating aspect of a Paternal Ancestry Signature is that it does not uniquely identify you as a single individual, but uniquely identifies your paternal line back through history that extends beyond written records.
Your Paternal Ancestry Signature is made up of 24 different data points (called 'loci' or 'markers') that are analyzed for the number of repeats at that location. These repeats are known as STRs (Short Tandem Repeats).
Using Your Results
The raw numbers begin to take on genealogical significance when you compare your results with other people and population studies. Your full Paternal Ancestry Signature is like a family fingerprint that identifies your paternal male relatives.
Matching Your Signature with Other Individuals
There are two primary sources of data for individual comparison:
Ancestry's DNA Databases - Ancestry.com has the world's largest database of Paternal Ancestry Signatures (Y-chromosome analysis). These databases are full 24-marker signatures and have a much higher resolution than the 12 or less marker databases available elsewhere. As the database grows and new matches are found, these matches will be presented on your personal genetic results web page. The information provided on the matches depends on what permissions were given by that person.
Group DNA Submission - The most common and informative use of your Paternal Ancestry Signature is to submit multiple samples from people you suspect share a common surname relative. The number of matches can be used to approximate the number of generations that separate the people tested.