yDNA and the Main Group of Kerry O’Sheas (BY402+)

This group of O’Sheas/ Sheas originated in Co. Kerry, Ireland about 1000 years ago. This means that the estimated time to a common male line ancestor for the O’Sheas who are BY402+ is about 1000 years ago. Although, we understand that these O’Sheas originated in Co. Kerry, some migrated to Limerick, Clare and around the coast into Cork, possibly hundreds of years ago. Others emigrated to other countries over the centuries.

Until the Big Y next generation testing came along, we relied on markers (ySTRs) but now we can combine SNPs (from the Big Y) and ySTRs to establish a better structure of this branch of the y-haplotree for these men.

Note that O’Sheas referred to here, have values on markers DYF406S1 and DYS617 which are indicative of being positive for the L513 SNP.  The mutations from 10 to 11/12 on DYF406S1  and from 12 to 13 on DYS617 are key values. However, with SNP testing and Big Y-700 results, we now also know that these O’Sheas are also on the BY402 branch of the y-haplotree. The hierarchy for SNPs on this branch of the y-haplotree is: L21>DF13>L513>S6365>BY16>Z16372>BY34582>BY404>BY402

Men in this group of O’Sheas also have a value of 16 on marker DYS650.  21 is the modal value for L21+ men and 16 is very  unusual even in L513+ men.  So,  having a value of 16 on DYS650, in conjunction with other mutations mentioned here,  is a good indicator of fitting the criteria for inclusion  in the BY402+ group of O’Sheas.

The R1b SNP Pack: R1b-S6365 contains some of the SNPs relevant to the L513+ Kerry O’Sheas but it has been superceded by the Big Y-700 test.

The BIG Y-700 test uses next-generation sequencing to find known SNPs and to discover previously unknown SNPs. Its main goal is to find SNPs which can be used as branch markers.  As more and more people do the Big Y-700  test, SNPs being discovered which are helping to subdivide lineages down to quite recent times.

The Big Y-700 test also includes ySTRs (markers).  So, after the Big Y-700 men have about 700 ySTRs (markers) and SNPs indicating the most advanced information about the position of their yDNA on the y-haplotree.

Big Y-700 Results for Members of the main Kerry Group

We believe that the BY402 SNP is likely to be present in all O’Sheas in the main Kerry subgroup. The Big Y-700 test has also revealed that BY402 splits into two branches identified by SNPs: FT47369 and BY408.

So far, the majority of BY402+ O’Sheas, who have done the Big Y-700 test, fall into the BY408 category. BY408 has been further subdivided into various branches. These branches are BY11251, BY3150, BY98138 and in turn these branches have been further subdivided. Refer to the diagram below. Note that the timeline is an estimate and will be refined as more information is obtained.


BY402+ O’Sheas

We have a lot more to learn about the FT47369 branch. So far just three men have tested positive for FT47369 with no discovery yet of further branches below this SNP.

Certain markers are being used to try to predict where O’Sheas, who match others already in the BY402+ group, fit onto the BY402+ structure shown in the diagram above. Various ySTRs (markers) are used for this. In the above diagram, some of the relevant mutations are shown in red. For example, DYS391 mutates from 11 to 10 and Y-GATA H4 mutates from 11 to 10 in the BY3150 sub-branch.

The O’Shea yDNA Project encourages O’Shea men to do the Big Y-700 DNA test.

Updated July 2020