The Original “Atlantic Modal Haplotype” (AMH)


The “Atlantic Modal Haplotype” was a phrase coined by population geneticists to refer to the most common haplotype in Europe.  At the time, there were typically only six Y-STR markers included in their studies, DYS019, DYS388, DYS390, DYS391, DYS392, and DYS393.  The most common haplotype was 14-12-24-11-13-13, or in the FTDNA order this becomes 13-24-14-11-. . . -12-. . . -13-….  When this haplotype was first identified, the YCC nomenclature for haplogroups had not yet been developed, so it was first considered to be a member of “Haplogroup 1”.  Now this haplogroup is known as Haplogroup R1b.


The “Western Atlantic Modal Haplotype” (WAMH)


Once Family Tree DNA established their 12-marker test as the basic standard in the field, it became possible to determine the most common 12-marker haplotype in Europe, and this was found to be (in FTDNA order):




Since, strictly speaking, the term Atlantic Modal Haplotype referred just to the six-marker haplotype, FTDNA invented the name “Western Atlantic Modal Haplotype” for this 12-marker haplotype.


The “Super Western Atlantic Modal Haplotype” (SWAMH)


As more markers became available for testing, particularly the 25-, 37-, and 67-marker panels from FTDNA, it became possible to determine larger R1b modal haplotypes.  Here is the R1b modal haplotype at 25 markers:




However, there could be a difference between the most common haplotype in the database and the artificial haplotype above that is composed of the modal values on each individual marker.


For example, on 19 January 2010 I searched Y-Search using the 25 individual marker modal values and I found only 43 matches, and 11 of these had the same surname.  So, out of the thousands of R1b haplotypes, only a few haplotypes will match exactly the modal values even at 25 markers.  Therefore, with such small numbers, it becomes almost meaningless (with the currently tested population) to speak of a “most common haplotype”—very few 25-marker haplotypes have other matches, except within the same surname.


When this same exercise is repeated at 37 markers, there are no exact matches to the 37-marker modal values in the Y-Search database, even omitting DYS456 and CDYa, which each have two values that compete to be the modal value.  Obviously, there will also be no haplotypes in Y-Search that would match the 67-marker modal values.


Here is the 37-marker Super Western Atlantic Modal Haplotype, which (as mentioned above) probably does not yet even exist in FTDNA’s database:




We can add the next 30 markers for the 67-marker SWAMH: