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A Y-STR is a short tandem repeat (STR) on the Y chromosome. Y-STRs are usually designated by DYS numbers. The standard Y-chromosome (Y-DNA) test used for genealogical purposes looks at Y-STRs, called Markers.


Y-STR allele nomenclatures

DNA testing companies or labs in certain cases use different nomenclatures to designate the same Y-STR allele. Thus, a conversion must be applied in these cases to accurately compare Y-STR results obtained from different companies. The most common nomenclature is based on guidance provided by NIST for Y-STR markers historically reported differently by various companies. The NIST standard is the proposal of ISOGG for genetic genealogy companies. [1][2]

  • from FTDNA to NIST: In FTDNA Projects the Haplotypes (STR Values) are formatted in the FTDNA lab standard (v1 until 2008, v2 since 2009?). For conversion from FTDNA v2 to NIST (ISOGG) standard used in scientific studies the following conversion apply:
    DYS441 +1, DYS442 +5, YGATAA10 +2, GATA H4.1 +1.
  • from NIST to FTDNA: DYS441 -1, DYS442 -5, YGATAA10 -2, GATA H4.1 -1. Sometimes DYS389II-I is listed; both values need to be summed.
  • from ISFG to FTDNA: same as for NIST except for GATA H4.1 -10 (-9-1)

The Sorenson Molecular Genealogy Foundation has incorporated a conversion function in the Y-Database Search on their homepage.[3][4][5]

Y-DNA STR Haplotype Databases

The following is a list of databases containing publicly submitted surnames and Y-STR haplotypes:

Y-DNA STR frequencies

NIST resources


  1. "Marker Standards". Sorenson Molecular Genealogy Foundation. http://www.smgf.org/ychromosome/marker_standards.jspx. Retrieved 11 August 2012. 
  2. Gale Matthiesen, Diana (19 July 2011). "Converting Y-DNA STR Test Results between SMGF, AncestryDNA, and FamilyTreeDNA". http://dgmweb.net/DNA/General/ADNA_FTDNA.html. Retrieved 11 August 2012. 
  3. SMGF marker standards
  4. Molgen Forum discussion, Aug 2012
  5. SMGF Y-chromosome search

External links

See also