Q: What is YFull's STR Comparison Methodology?

A: The comparison of your STR results with the STR results of other database samples is contained in the STR matches report available from the menu on your YFull account home page. When you select this menu item, the next page allows you to select a sample (if there is than one in your account). Select the Submit button to call for your report. You may print a copy of your Close matches and, separately, a copy of your Distant matches.

The STR matches report provides information about samples in the YFull database that match your sample (or the selected sample), and classifies the matching samples as Close or Distant. Only samples that have an estimated age of 5000 ybp or younger (using TMRCA from the YTree) are included in the report.

Close matches are defined by YFull as matches with a genetic distance of less than 0.050, and Distant matches as matches with a genetic distance of 0.050 to 0.085.

The formula for calculating genetic distance is the number of Differences divided by the number of Compared STRs. For example: 49/392 = 0.125.

To apply the YFull formula to a STR test obtained from a DNA testing company, multiply YFull's calculated genetic distance by the number of markers in the test. For example: apply 0.125 x 67 (markers in a test) = 8.375 (rounded to 8 and thus a genetic distance of 8 in a 67 marker test).

The "infinite alleles model" mentioned in the footnote to the table is a mathematical model for calculating genetic mutations.

Last updated on March 28, 2018.