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R1b-CTS4466 Plus

  • 1359 members

About us

CTS4466 is the SNP that defines the Irish Type II subclade, which was identified by the respected physicist and nonpareil citizen scientist Dr. Ken Nordtvedt in 2006.  It was recognized by its distinctive haplotype prior to the discovery of any SNPs associated with it. In 2011, multiple attempts to find a defining SNP through the Walk Through The Y test offered by Family Tree failed, but at the end of 2012, the more comprehensive Geno 2.0 test through National Geographic finally gave us success with two SNPs – CTS4466 and CTS5714.  Then the 1000 Genome project added two more – CTS3974 and CTS8358. Since then, an increasing number of other SNPs have been discovered through the other extensive SNP tests mentioned at the bottom of the page, particularly the BIG Y test.


The R1b-CTS4466 Plus project will research the parameters of this major subclade which features strongly in the south of Ireland, but it is found as well in other areas of the Isles, including some in the west of Ireland, Wales, western England, an apparent branch in Northern Ireland and Scotland and a few continentals.  We hope to discover the ancient history of this subclade - where it may have originated, how old it might be, which groups within it share more recent ancestry and how different branches may have developed and migrated from the time of the common ancestor.

Membership Criteria

To meet the objectives of the project, we seek to limit membership to those who have tested positive for at least one of the SNPs defining Irish Type II or have a haplotype consistent with that identified through research in the Family Tree DNA database.
Interested parties are invited to join, even if not SNP tested, with the understanding that the Project Administrators will review the participant’s haplotype and, at their discretion, determine if there is a likelihood of it proving positive for the defining SNPs. If accepted, we expect that the participants will be willing to test for further SNPs as suggested, based on the discoveries as we progress.

Those who are deemed not to meet these criteria will be asked to leave the project or accept that the Project Administrators will remove them from it.

The Irish Type II Modal

We cannot know what the actual haplotype was of the first man to carry the distinguishing SNP/s that define the Irish Type II haplotype, but as Nigel puts it, logical reasoning gives a pretty good guess at what the ancestral haplotype was just 2000 years ago; just one or two loci may be in doubt.  The Irish Type II modal is a compilation of the most common values of a particular haplotype. 

The modal for the SNP L21 super subclade is the base used to arrive at the Irish Type II modal. There are twelve markers where the value for the Irish Type II differs from the L21 modal. Five are one step up from the L21 and seven are one step down. 

CTS4466 Modal

The SNPs associated with Irish Type II

The Results spreadsheet has been updated and reorganized to match the order in Family Tree's Haplotree (which each kit can access through their 'Haplotree & SNPs' link).  Our list of SNPs below has also been updated to reflect that order.  We have limited the list to only display the lead SNP of each branch except in the few instances when some kits have a terminal SNP of an equivalent, based on the type of SNP test they took to identify their terminal SNP.  A '/' indicates equivalents. 

We can sometimes get a bit behind in updating the tree here with newly identified branches, but the DNA Results Charts should be accurate.  If you see any errors or omissions, please bring them to our attention.

Latest Background Tree as of 04 December 2022; 5 new SNPs since 14 November 2022:

—————————FTC91111 (NEW)
————————FGC42471 (NEW)
——————————————FTC43511 (NEW)
————————FT47401 (NEW)
———————————FTD35695 (NEW)

The CTS4466 tree has expanded tremendously since our first meager chart in 2014, and as we receive more BIG Y and other NGS results, we continue to identify more branches. There are a number of SNPs currently equivalent to CTS4466. While CTS4466 is being used as the 'flagship' SNP, since it was identified first, any one of them may be the first or last of this series of SNPs occurring perhaps during the Bronze Age and likely into the Iron Age, defining the Irish Type II subclade before branches which have survived to this day began to appear.

SNP Testing Options

FTDNA offers individual tests for a number of SNPs.  The price per SNP is $39. Please ask for advise re your situation prior to purchasing a SNP test.  

FTDNA introduced a CTS4466 SNP Pack in early 2015.  It tested for all known branches of the CTS4466 tree at that time.  Its results are incorporated into the participants' Haplotree & SNPs link and display the terminal SNP in the Badges box on the left of their home page.  The Pack was updated to include newly identified branches in 2017, but by now the number of branches has far exceeded the capacity of the Pack testing.  At this point, it seems unlikely that Family Tree will upgrade the SNP Pack to be terribly useful.  New branches can only be identified through the BIG Y test, and with the price being far more affordable than it was at its outset, it is the preferred choice for SNP testing. I would suggest that any SNP test short of the BigY will leave the tester with more questions than answers.

The Big Y-700 includes 700 STR markers including Y111. We advise members to wait until a sale is in force before purchasing a test/upgrade. The additional STRs that are captured by the Big Y test don't display on the Results spreadsheet, but they are reported on the Big Y STR Results link.  Later STRs are generally less volatile that those in the Y111 sets and are useful when comparing more distant relationships.  Nigel uses them in developing his IT2 Phylogenetic Tree.  Family tree have more details about the test at their link:

The BIG Y test provides a dedicated Big Y Results page with details of Matches, Named Variants, Private Variants and a Block Tree, displaying neighbouring branches and individuals in those branches listed on the Matching link.  It has a link to Export (CVS) that can be downloaded that contains all that data displayed.  In addition, the participants can Download Raw Data that has more information, and if they pay an additional fee, they can request a BAM file which has all the raw data for further analysis.  Unless the participant is comfortable with handling large files (they're really huge) we don't recommend they try to analyse them themselves.  We suggest that all BIG Y testers load the VCF folder as well as the link to the BAM file, if they order it, to James' Y-DNA Warehouse at

R1b-CTS4466 Plus Haplogroup Forum

We have moved to a new forum at for those whose paternal ancestry places them in the CTS4466/Irish Type II haplogroup/subclade. There we can network with one another, pool our efforts, discuss research and share results. Members of the project are not required to join, but you are encouraged to participate if this sparks your interest.  Likewise, you need not be in the project to join the forum.  If you are confused by any of the science, terminology, FTDNA's website, or anything else relating to the project or genetic genealogy in general, please feel free to post your comments, questions, and concerns in the R1b-CTS4466 Plus group.  

R1b-CTS4466 Plus FAQs

We've prepared a brief document with some of the questions we receive from participants.  It is available in the files section of the Forum.

R1b-CTS4466 Plus Project Privacy Statement

As Administrator and Co-administrators of the R1b-CTS4466 Plus Project, in addition to abiding by the Privacy Policy that Family Tree posts, we wish to assure you that we give you, as a member of this Project, our priority in protecting your privacy and the confidentiality of your personal data.

What personal data about you do we hold or have access to?

The only personal data about you that we hold or have access to is data which has been made available to us by Family Tree DNA with your consent, to the access level you have chosen, and additional data which you may have given us directly by e-mail.

What use do we make of this personal data?

The only use we make of this data is that relevant to meeting the goals of our Project.  These goals require Project Administrators to be able to review the participant’s haplotype and, at their discretion, their personal data to determine and advise the project member on potential additional testing for the participant’s and the project’s benefit.

We would not publish or share your full name, e-mail address or other contact details with any other project member or other person or organization without your specific written approval, unless we were legally obliged to do so.

We will not publish or share your DNA test results except in anonymized form, limited to kit number and surname or ancestral surname.  The Results spreadsheet on our website also contains your Paternal Ancestor Name and Country of origin.

How long do we hold this personal data?

We hold this data for as long as you remain a member of our Project.  If you wish to withdraw from our Project you may do so by clicking the ‘Leave’ button on the Project Preferences link of your Account Information page.  Any posts on our R1b-CTS4466-Plus Forum can be deleted, but we cannot retrieve information that may have been previously posted in a public domain.  We would do our utmost to identify and delete any emails you have shared with us if you request us to do so.

In our administration of this Project, along with Family Tree’s commitment to you, we will comply with the requirements concerning the privacy of project members that are contained in the European Union’s General Data Protection Regulation which enters into force on 25 May 2018, regardless if you reside in the EU or elsewhere.

We endeavour to respond promptly to any queries, errors or complaints you may bring to our attention about our handling of your personal data associated with this Project.

We may update this Statement as circumstances arise.

Last updated 05 December 2022