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Y-DNA FTDNATiP™ Calculator

The Time Predictor, or FTDNATiP™, is a program that incorporates Y-chromosome DNA STR mutation rates to increase the power and precision of estimates of Time to Most Recent Common Ancestor (TMRCA).

Accessing the FTDNATiP™ Calculator

You can access the FTDNATiP™ Calculator from your Y-DNA Matches Page.

To access from your dashboard:

  1. Sign in to your kit.
  2. On your dashboard, locate the Y-DNA Results & Tools widget.
  3. On the Y-DNA Results & Tools widget, click the Y-DNA Matches button. 
  4. Select the match you would like to use the FTDNATiP™ Calculator with.
  5. Click the Time Predictor icon on the right-hand side of the page next to that match.

To access from your navigation bar:

  1. Sign in to your kit.
  2. On the navigation bar at the top of the page, go to Results & Tools > Y-DNA >  Matches.
  3. Select the match you would like to use the FTDNATiP™ Calculator with.
  4. Click the Time Predictor icon

Understanding the FTDNATiP™ Calculator

The Y-DNA TiP Report will automatically generate a chart containing probability estimates of TMRCA. Since mutations do not occur every generation, the estimate of the TMRCA is not an exact number (e.g. seven generations) but rather a probability distribution. Different STR markers tend to mutate at different rates, and the probabilities take into consideration the mutation rates for each individual marker being compared. Since each marker has a different mutation rate, identical Genetic Distances will not necessarily yield the same probabilities.

As more markers are compared, the TMRCA estimate becomes more refined. However, there are diminishing returns after a certain number of markers. For exact matches who share a surname, this is usually at about 67 markers. Close but not exact matches at the Y-DNA37 or Y-DNA67 level can benefit from upgrading to Y-DNA111.

Using the FTDNATiP™ Calculator

Below the column of the results controls to alter the number of markers used for comparison and the number of generations to be displayed. You can refine these results by lowering the number of generation increments listed in the chart, to as few as every generation. A generation is generally considered to be approximately 25 years, so you will be able to approximate the number of years to the common ancestor by multiplying the number of generations by 25.

This tool also allows you to incorporate your solid genealogical paper trail information on the earliest possible generation of a common ancestor into the DNA match calculations. For example, if you can exclude any chance of a common relative between you and another individual within (say) the past three generations, you enter this information, and FTDNATiP™ computes the time to common ancestry based on both the STR marker pattern and your information that the common ancestor must be at least four generations back.

If you wish to compare a match at a specific marker level, select that match while viewing your Y-DNA matches at the desired match level. For example, if you match an individual at both 67 markers and 111 markers, but wish to compare them only at the 67 marker level, you must click the Time Predictor icon while viewing your 67 marker matches on your match page.

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