How do I find out the time to the most recent common ancestor in years?

You can convert from generations to years by multiplying the number of generations by an average number of years between generations. In general, you can use an average of 25 years per generation, although the […]

Do all FTDNATiP™ calculations offer the ability to add genealogical data? Why don’t you always show it?

When using the FTDNATiP™ calculator in myFTDNA, the box in which to enter the number of generations appears only when you are not comparing a perfect match, i.e., when there are mutations between the two […]

Will testing additional STR markers improve FTDNATiP™ calculations?

Yes, a higher number of compared Y-DNA STR markers does increase the power and accuracy for Time to Most Common Ancestor (TMRCA) calculation. However, there are diminishing returns after a certain number of markers. For exact […]

Bob, John, and I have the same Genetic Distance. However, when compared, we have different probabilities for sharing a common ancestor, for example, within eight generations. Why?

FTDNATiP™ uses both the number of mismatches and the mutation rates of individual markers in calculations. This means that although two men may have the same number of mismatches, they may not have the same […]

Why did the FTDNATiP™ probability become less when we eliminated the possibility of a common ancestor within the past seven generations? It seems that it should increase?

These are cumulative probabilities. That is the key to understanding something that initially seems counter intuitive. Let’s use an example for a specific situation of one mismatch in 37 markers. Before inputting your information, the […]

When comparing two individuals, the DNA test shows them to be closely related. However, one has my surname and the other does not. Does the match with the similar surname mean we are more closely related?

In many cases, you are more likely to be recently related to a match who also shares your surname. However, there are several reasons why recently related individuals may not share the same surname (undocumented […]

Why does the Report page sometimes show a difference between the Genetic Distance and the number of mismatches?

This is because genetic distance and mismatches are two different comparisons. FTDNATiP™ uses mismatches in its calculations.* *FTDNATiP™ uses the infinite allele model as opposed to the stepwise model for all STR markers. See also: […]

Who is one generation ago?

FTDNATiP™ calculations start counting generations with the parent generation. Therefore, the father of the person tested is generation one, the paternal grandfather generation two, etc.

I have genealogical information. How does FTDNATiP™ use it?

FTDNATiP™ 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 […]

Y-DNA Matches – FTDNATiP™ Tool

FTDNATiP™ (FamilyTreeDNA’s Time Predictor) is a program that predicts the time to the most recent common ancestor for two men based on their Y-chromosome STR matching and STR mutation rates. FTDNATiP™ provides powerful and precise calculations of […]

I am using FTDNATiP™, and I cannot change the number of generations for some comparisons. What is wrong?

For your exact matches, the calculation is not changed by known generations. Therefore, the option to change the number of generations is not available. When using FTDNATiP™, you are only given the option to change […]

What is the FTDNATiP™ Calculator, and how do I use it?

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