TMRCA Case Studies

  • 406 members

About us

News release dated May 2015:
Project and paper update:  


     For the detailed workbook, join the Yahoo TMRCA forum at Under files, see 'aaa CTS4466 paper and workbook 11252015 - not for public use'

See the FTDNA TMRCA Case Study project for a list of our current research.  

Concurrent research projects:

A212/A218 - formerly known at T2-C - Ron McRaney admin

A151/A152 - formerly known at T2-D - looking for admin

        Both sub branches above have members with predominately Scots-Irish heritage:

There is much we have learned from our SNP analysis when applying TMRCAs to the subbranches.  For example the 4466-T2-C group, now testing positive for A212/A218, is just younger than the CTS4466 SNP itself.  This group has family histories in Northern Ireland and Scotland.  There were historical writings that they had were Eoganacht descendants that migrated northward during times of famine and had been part of the Dal Raida of Southern Ireland.  The current dating of the A212/A218(4466-T2-C) brings this into question,although it doesn’t nullify the possibility it opens up reasonable doubt simply due to the TMRCA for the SNPs.  Did their ancestors migrate directly from Iberian lands northward? The dating of a SNP provides immense knowledge to those who belong in these SNP sub branches.

Were the A151/A152 (4466-T2-C) perhaps the descendants of the Dal Raida?

S1121/L270 - Kathleen Kerwin admin

L270 has been found in 20 members.  12 of the 20 (60%)  testing L270+ are Sullivan’s with an additional 2 with no South Irish ancestry one a Scot and the other English, 3 with unknown history, with 1 with Daly and the other McCarthy surnames.  There is continuing to be a sub clan signature theme which is remarkable and meaningful.  4 of these Sullivan’s have only tested to 37 markers.  Reviewing the family histories of the sub branch members, it maybe that L270 is decidedly Sullivan Beare for the most part.  There is one McGillicuddy, which is a Sullivan cadet name for the Sullivan Mor clan. Is there a Sullivan Beare signature different from the Sullivan Mor?  Or perhaps more dominant in the former or the latter?  So much is left to be learned.  Of the three L270+ members who have taken the Big Y test, they all have additional unnamed SNPs that are decidedly different from each other which points to the fact that they will most likely split again.  Do the Daly and McCarthy L270+ also have different downstream sub SNPs?

Lineages: These sub branches have TMRCAs with 300 years before present and are considered lineages.  They have excellent family history and record documentation to prove there ancestry.

Macaulay - 4466

Thrasher - 4466

McGee - DF49


Our project goal is to identify the lineages of common ancestors by building phylogenetic family trees and branches using SNPs and STR markers.

The Case Study methodology is based on the work of Dr. Anatole Klyosov. He has documented his calculations for determining TMRCA (Time to the most recent common ancestor). We build a phylogenetic tree with the yDNA results and then run them through Anatole's calculations to see if the yDNA results are within a reasonable range (80+%) or within 250-300 years. If yes, this is considered a lineage.

The work being done for the South Irish project can be reused for any base haplotype. It has expanded to "Research when the 4466 SNP occurred in the phylogenetic tree that includes both the Iberian descendants similar to the South Irish base haplotype and those with the South Irish base haplotype, the results of which will also identify the Iberian Ancestors of the South Irish base haplotype".

We are creating a methodology and framework to help volunteers build their own SNP/STR family trees and branches. Everyone can share information and ask questions in this forum.

The documentation for the building of family trees and branches will be written so anyone and everyone can start their family tree from scratch; see for the FTDNA Case Study Framework that helps to build family trees and branches. 

At present we have 790+ members in our 4 projects, in addition to including yDNA from over 20+ other projects.

Kathleen Sullivan Kerwin, administrator

The related TMRCA calculations and phylogenetic base haplotype relationships are based on work from Dr. Anatole Klyosov.

Papers in progress:

-4466 TMRCA Case Study using a forensic yDNA approach

-TMRCA Case Studies in lineages using a forensic yDNA approach

-Eoganacht sept name variants and base haplotypes

Also see related projects: FTDNA Eoganacht septsSullivan and TMRCA Case Study

Eoganacht septs website: describes the relationship between Eoganacht surnames, 4466+ and the South Irish base haplotype

Related forum: TMRCA Case Study - you are welcome to join and ask questions

We also welcome all R-L21 members, as well as any other members who are serious about the research of their yDNA ancestry.  The TMRCA Case Study research group includes all FTDNA members.

Admin:Kathleen Sullivan Kerwin

Co-administrator: James Kane; bioinformatics developer

Co-administrator: Ron McRaney; our right hand, A212/A218 admin, and reviewer