Western Atlantic Modal Haplotype Badge

If you have a Western Atlantic Modal Haplotype Match badge in the Badges section of your dashboard, it means that you match or are close to the historic Western Atlantic Modal Haplotype (WAMH) that has […]

Niall of the Nine Hostages Badge

If you have a Niall of the Nine Hostages badge in the Badges section of your dashboard, this means that you match exactly or are a close match to the historic Irish Modal Haplotype (IMH). […]

Which Y-DNA STR markers do FamilyTreeDNA test?

At FamilyTreeDNA, we test 561 Y-chromosome DNA short tandem repeat (STR) markers in our standard Y-STR tests: Y-DNA12, Y-DNA25, Y-DNA37, Y-DNA67, Y-DNA111, and Big Y. The chart below shows a list of all markers offered […]

What is different about the STR markers DYS389I and DYS389II? Why is my DYS389II (DYS389-2) result at FamilyTreeDNA different from the Genographic Project?

The Y-chromosome DNA (Y-DNA) marker DYS389 is a single STR marker that has four parts: m, n, p, and q. At FamilyTreeDNA, we have two tests for DYS389. The first test looks at the first two […]

Do more Y-DNA STR markers improve the quality of matches’ information?

You should test more Y-chromosome DNA short tandem repeat (STR) markers when you wish to compare additional markers against others with similar results. They will refine your matches for genealogical purposes. It does not increase the […]

Don’t we all go back to Africa?

Yes. All of our Y-chromosome lineages trace back to a common ancestor who lived in Africa at least 115,000 years ago. Some lineages migrated out of Africa; others remained. This map shows each of the major […]

How does the infinite allele comparison method work for palindromic markers?

For palindromic markers, the infinite allele method counts a difference for two types of changes: a mismatch and a copy number change. Mismatches occur when the compared markers do not match. For example, the first man […]

How many generations does a Y-chromosome DNA (Y-DNA) STR test trace?

Y-chromosome DNA (Y-DNA) tests trace both recent and distant generations. The number of generations traced by a Y-chromosome DNA test depends on the type of test taken, short tandem repeat (STR) or single nucleotide polymorphism […]

Why do I have more than one result for an STR value? What is a multi-copy STR marker?

A multi-copy STR marker is one where there are multiple versions of the same STR in different locations on the Y-chromosome. Each STR copy changes independently. Therefore, it is typical to have different values for […]

What is the likelihood of a non-paternal event or false paternity?

We believe that the rate of unannounced adoption or false paternity is about 1 – 3% per generation and compounds each generation. When confirming your lineage, we recommend that you test yourself and your most […]

What does each short tandem repeat (STR) marker mean?

By themselves, Y-chromosome DNA (Y-DNA) short tandem repeat (STR) markers from a Y-DNA test do not have any particular meaning. The value of testing Y-DNA STR markers comes from creating a Y-DNA signature (haplotype) with […]

Why don’t my Y-chromosome DNA (Y-DNA) test results show me percentages?

Your Y-chromosome DNA (Y-DNA) test results cannot be used to indicate your percentage of DNA from different ancestral groups. This is because tracing your Y-DNA line only leads to one origin. Y-chromosome DNA Inheritance 1 […]

If somebody doesn’t match me at 12 markers, how can they match me at a higher testing level?

Aside from their having matching turned off at the Y-DNA12 level, someone might match you at a higher testing level but not Y-DNA12 because the genetic distance is more than the amount allowed for Y-DNA12 […]

If two men share a surname, how should the genetic distance at 111 Y-chromosome STR markers be interpreted?

In cultures where surnames are passed from father to son, there is additional evidence beyond a DNA match that two men who share a surname are related. Y-chromosome DNA (Y-DNA) test results should be interpreted […]

If two men share a surname, how should the genetic distance at 67 Y-chromosome STR markers be interpreted?

In cultures where surnames are passed from father to son, there is additional evidence beyond a DNA match that two men who share a surname are related. Y-chromosome DNA (Y-DNA) test results should be interpreted […]

If two men share a surname, how should the genetic distance at 37 Y-chromosome STR markers be interpreted?

In cultures where surnames are passed from father to son, there is additional evidence beyond a DNA match that two men who share a surname are related. Y-chromosome DNA (Y-DNA) test results should be interpreted […]

If two men share a surname, how should the genetic distance at 25 Y-chromosome STR markers be interpreted?

In cultures where surnames are passed from father to son, there is additional evidence beyond a DNA match that two men who share a surname are related. Y-chromosome DNA (Y-DNA) test results should be interpreted […]

If two men share a surname, how should the genetic distance at 12 Y-chromosome STR markers be interpreted?

In cultures where surnames are passed from father to son, there is additional evidence beyond a DNA match that two men who share a surname are related. Y-chromosome DNA (Y-DNA) test results should be interpreted […]

Expected Relationships with Y-DNA STR Matches

The expected relationship between you and your Y-chromosome DNA (Y-DNA) match is dependent on both the number of markers you have tested and the genetic distance. The chart below shows the interpretation of your relationship […]

Y-DNA Genetic Distance

When talking about two or more Y-chromosome STR (short tandem repeat) haplotypes, genetic distance is the total number of differences or mutations between two sets of results. In general, it is found by summing the […]

Y-DNA Step Mutations

When comparing the results of Y-chromosome STR (short tandem repeat) tests, the difference between the two values at a marker is the Y-DNA genetic distance or the step-mutation count. That is, a one-step mutation means […]