The response from Dr Ken Nordtvedt said that my markers matched a small cluster that he later identified centred on the counties of Clare, Limerick and Tipperary in Ireland. He detailed the markers that defined the cluster and I matched. I was most surprised by this as I had expected my roots were in England. As two other Irish clusters had been identified as "North West Irish" and "South Irish", I started calling this cluster "Irish Type III" and the name has stuck.
The definitive markers Ken identified for this cluster are:-
Initially FTDNA were not testing DYS463 so the nomenclature for this marker in ySearch was that used by DNA Heritage which was 2 points lower than the NIST/ISFG standard. As of 01 March 2010, the value of this marker in Ysearch has been brought into line with the NIST/ISGF standards. If you have been tested at FTDNA, Ancestry or Genebase, enter this marker value as reported by your lab.
As no one else had taken an interest in researching this cluster, I started to gather examples from Ysearch, Sorenson (SMGF), Ancestry and various Surname Projects. In December 2006 I started these webpages to share the data I had collected. We now have over 726 members in the cluster.
Common Surnames are O'Brien/Brien/Bryan/Bryant, Butler, Casey, Crow(e), O'Donoghue, Hart, Hogan, Kennedy, McCraw/McGraw/McGrath, McNamara. Most seem to be Dalcassian clans, the descendants of Cormac Cas and Brian Boru. There is other evidence that this is the signature of Brian Boru and Kings of Thomond.
My paper, A Set of Distinctive Markers Defines a Y-STR Signature for Gaelic Dalcassian Families, will be of interest to members of the cluster and has been published in the Spring 2009 issue of Journal of Genetic Genealogy www.jogg.info A copy can be downloaded at www.jogg.info/51/files/Wright.pdf
The SNP L226 is the defining marker for this haplogroup. Testing positive for L226 is final confirmation that a haplotype is part of the Irish Type III haplogroup. This marker can be ordered from your FTDNA Home Page. Go to your Home Page / yDNA / Haplotree / and under 'Choose your own SNPs', click on 'Continue to choose SNPs' Now scroll down the chart to [L226!] in Orange near the bottom. Click on this and it will appear in the list above the chart. Now click on the 'Continue Order' button to process your order. If you order this marker, please also join the R-L226 project, http://www.familytreedna.com/public/R-L226_Project/default.aspx