Western Atlantic Modal Haplotype
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In human genetics, the Western Atlantic Modal Haplotype (WAMH) is the most frequently occurring 12-marker Y chromosome haplotype associated with haplogroup R1b1a2, the most common haplogroup in Europe. The term was invented by Family Tree DNA to differentiate the newly found 12-marker signature from the six-marker haplotype known as the Atlantic Modal Haplotype. FTDNA customers who have a WAMH match will have a coloured badge (see right) on their personal page. The WAMH badge is triggered when the customer has an exact match with one of four 12-marker R1b1a2 haplotypes:
As of November 2012 males with the WAMH badge can have between 2500 and 7500 12-marker matches in the FTDNA database. It is therefore recommended that men with this haplotype should always upgrade to the 67-marker or 111-marker test for genealogical matches and to rule out false positive matches.
WAMH exists in high or very high frequencies in all of Western Europe from Spain in the south to the British Isles and western Scandinavia in the north. Family Tree DNA estimate that approximately 1.3% of males in Western Europe share this most common genetic 12-marker signature. As a result of the rapid population expansion in the last 4000-5000 years the lineages within R1b1a2 have experienced convergence. As part of the random mutation process more distant lineages have moved closer together producing coincidental matching haplotypes. SNP testing is therefore recommended to eliminate such coincidental matches. If two men are in different subclades of R1b they will be on different sub-branches of the Y-SNP tree and will not share a common ancestor within a genealogical timeframe. SNP testing will also allow the participant to join the relevant R1b subclade project.
WAMH is the modal haplotype of R1b-L11 and predominates in two subclades of L11 - R1b-P312 and R1b-U106. It is also common in R1b-L21, a subclade of P312. It is recommended that anyone with the WAMH who wishes to determine their R1b subclade should join the R1b and subclades project and seek advice from the project administrators about which tests or individual SNPs to order. Alternatively advice can be sought from the R1b mailing list. It is sometimes possible to predict a more downstream subclade of P312 or U106 from a 67-marker haplotype. If the participant has close matches at 67 markers the prediction can sometimes be informed by the SNP status of his matches. Single SNPs can be ordered from FTDNA or YSEQ.
- The "Western Atlantic Modal Haplotype". An R1b resource page compiled by Whit Athey.
- What does the WAMH badge on my personal page mean? Family Tree DNA FAQ id 410.
- What does the WAMH badge on my personal page mean? Family Tree DNA FAQ
- A PNAS article on the Atlantic Modal Haplotype and variations in the British Isles
- Atlantic Modal Haplotype tutorial from DNA Heritage (Internet Archive version) N.B. DNA Heritage was acquired by Family Tree DNA in 2012.
- Common haplotypes by Georgia Kinney Bopp
- Wikipedia page on the Atlantic Modal Haplotype
- Wikipedia article on R1b
- R1b and subclades project
- R1b mailing list