The Y-DNA – Standard Y-STR Values page shows the results of standard Y-DNA short tandem repeat (STR) tests: Y-DNA12, Y-DNA25, Y-DNA37, Y-DNA67, Y-DNA111, and Big Y-500.

The following are descriptions of special characters that you might see on your results page:

  • ¤ This result is new since your last sign in.
  • * A value of “0” for any marker indicates that the lab reported a null value for this marker. Our labs retest all cases of null values multiple times to confirm their accuracy. Mutations causing null values are infrequent, but fathers pass on null values to their sons just like other Y-DNA mutations. Therefore, related male lineages such as a father and a son are likely to share null values.
  • ** DYS19 is also known as DYS394.
  • *** The Family Tree DNA and the Genographic Project report DYS389II differently.
  •  For Panel 6 (112-561) Y-STR results, a – is displayed when you have a “no call” result for an STR. A “no call” result means that we do not have enough information for that STR to confirm a value.
Why do some of my Big Y-500 (Panel 6) allele values differ from results I've received from other companies?

At FamilyTreeDNA we typically count only perfect repeats; therefore, some of the Big Y-500 (Panel 6) Y-STR allele values will consistently differ from that of other companies. The difference will be offset by only a few values above or below the results you’ve received elsewhere.

What do the DYS, DYZ, DYF, and FTY prefixes on Y-DNA STR names mean?

DYS, DYZ, and DYF Prefixes 

The DYS, DYZ, and DYF prefixes are part of the scientific name for a short tandem repeat (STR) found on the Y chromosome. STR markers are named according to guidelines published by the HUGO Gene nomenclature committee (HUGO). For Y-DNA STR tests:

  • D stands for DNA.
  • Y stands for Y chromosome.
  • S, Z, and F stand for the complexity of the repeat segment as follows:
    • S is a unique segment.
    • Z is a number of repetitive segments at one site.
    • F is a segment that has multiple copies on the Y chromosome.

FTY Prefix 

The FTY prefix stands for Family Tree Y. For now, this prefix acts as a placeholder until HUGO assigns an official prefix to these STRs.

Identification Number 

All STRs are given a unique identification number.

For example, DYS393: the D indicates that the segment is a DNA segment,  the Y indicates that the segment is on the Y chromosome, the S indicates that it is a unique segment, and the number 393 is the identifier.

What do the numbers on the Y-DNA - Standard Y-STR Values page mean?

The numbers and letters in the Y-DNA – Standard Y-STR Values page are the results for your Y-chromosome DNA STR tests.

The first row is the locus number in the test panel. For example, for the first panel (Y-DNA12 results) each locus is numbered 1 through 12.

The second row is the scientific name of each STR tested. Everyone who tests, respective to the Y-DNA12, 25, 37, 67 or 111 marker tests, is tested for the same STR markers at the same loci. 

The third row contains the allele values for each STR. These are the values that make up your DNA signature.

How many STR (short tandem repeat) markers have I tested?

You can determine how many Y-STR markers you have tested by checking the Y-DNA – Standard Y-STR Values page of your myFTDNA account. To do so:

  1. Sign in to your myFTDNA account.
  2. On your myFTDNA dashboard, in the Y-DNA section or the Big Y500 section, click on the Y-STR Results button to navigate to your Y-DNA – Standard Y-STR Values page. This page displays your Y-STR results.