The following guidelines are used for determining Lineages:
1. Member should have a Y-DNA 25 marker result or greater
2. A lineage is declared when 2 project members have a “time to most recent common ancestor” (TMRCA) of 850 years or less. This corresponds to the time period when surnames were commonly used and passed down to the next generation.
3. Time to most recent common ancestor (TMRCA) is based on Family Tree DNA’s Time Predictor, FTDNATiP. It provides powerful and precise calculations of “time to common ancestor” estimations by incorporating mutation rates specific for each STR marker.
4. Average generation time estimate is 30 years.