Overview of the Mutation History Tree v4 for Lineage II

The Gleeson's of Lineage II have origins in North Tipperary and all share a common ancestor about 1000 years ago. This common ancestor presumably also came from North Tipperary and was the first person to use the Gleeson surname in that particular area. But how are all these Gleeson's related to each other? What does the family tree for this entire group look like? This is where Y-DNA comes in. We can construct a "Mutation History Tree" (MHT) for the entire group by analysing the mutations in their Y-DNA markers. This tree stretches from the present day all the way back to the origin of the surname (about 1000 years ago) and back before that into the era of the Irish Clans.

The screenshot below is an overview of the MHT. However, it is best viewed by downloading the pdf version of the entire MHT v4 from this Dropbox link here. You can then read this text and refer to the pdf document when you need to see larger print. Alternatively, you can enlarge your webpage by holding down the Ctrl button on your PC keyboard (Cmd on a Mac) and clicking on the plus sign (+) button to enlarge the text or the minus sign (-) button to reduce it. Or you could open this post in two browser windows and flick back and forth between the text and the diagram below.

This Mutation History Tree (MHT) represents a "best fit" family tree for the available data. It probably does not reflect reality, but probably comes relatively close to it.

The MHT diagram below includes individual kit numbers & G-numbers on the left (anonymous kits are blanked out), followed by the branch name and then the branching structure of the MHT itself, starting at the present and going back in time from left to right. The numbers refer to STR markers that have experienced a mutation along a particular ancestral line. Parallel Mutations are in pink or blue, and the single Back Mutation is in red.

There is a very crude TMRCA timeline at the top (TMRCA = Time to Most Recent Common Ancestor) which is derived from various exploratory exercises with the SAPP Programme. All these technical details will be explained in a supplementary post and only the top-line conclusions will be presented here.

Gleeson Lineage II MHT version 4 - download pdf document here
(click to enlarge)

So what does the MHT tell us? Firstly, it points to a common ancestor for the entire group who lived about 1100 AD (+/- 200 years). He carried the SNP marker A5631 and passed it on to all his descendants.

Within a few generations (possibly around the time of the Norman Conquest of Ireland), at least 2 descendant branches emerged - one characterised by the SNP marker BY14197  the other by A5629  Both produced descendants that survive to the present day.

• BY14197 gave rise to  Branch F .
• A5629 gave rise to all the other named branches within the group.

There may be other "ancient branches" that remain to be identified - possibly 2 below A5631 and possibly 4 below A5629. Or alternatively, these branches (if they ever existed) have gone extinct.

Here is a short summary of each branch. Note that all dates are very approximate and most have a range of plus or minus 200 years:

• Starting at the top,  Branch F  has 5 members. They share a common ancestor who lived about 1500 AD. This ancestor carried the SNP markers BY14197 & BY14189 and passed them on to the entire group. This branch includes the oldest ancestral line within the project - the participant bears the unusual surname variant CLESSON and the MDKA goes back to 1651 in colonial America.
• Next, Branches B, A1 & A2 share a common ancestor who lived about 1450 AD and carried the SNP marker A5628 (which he duly passed on to all his descendants). 
•  Branch B  consists of 7 members whose common ancestor lived about 1550 AD and carried the SNP Y16880.
•  Branch A1  has 4 members whose common ancestor lived about 1700 and had the SNP A660.
•  Branch A2  has 3 members whose common ancestor was probably Matthew Gleeson (born about 1805) or his father, who came from Clonlara in Co. Clare. They may share an as yet unnamed SNP marker.
•  Branch E , the  C branches ,  D2  &  H  share a common ancestor who lived about 1250 AD and carried the SNP BY5706. By the time this branch emerged, the Norman's had a strong foothold in Ireland. This man had many descendant lines that survive to the present day, and among these are 4 distinct sub-branches.
•  Branch E  & the  C branches  share a common ancestor who lived about 1500 AD and carried the SNP BY5707. This later gave rise to the 2 separate branches:
•  Branch E  - common ancestor lived in the 1700s, possibly in or near Curraghneddy in Co. Tipperary
• Branches C2, C1 & C3  - common ancestor 1550 (had BY5707)
• Branch C2 - common ancestor 1650 (carried A13116)
• Branch C1 - common ancestor 1650 (carried A13110)
• Branch C3 - common ancestor possibly James J Gleeson (born 1844) 
•  Branch D2  is another ancient branch. The common ancestor of the 5 members lived about 1350 AD, around the time of The Black Death. He carried the SNP A13119.
• The members of  Branch H  (7 men) &  Branch G  (5 men) are difficult to place. Only 2 of the men have done the Big Y test and there is insufficient comparative data to allocate them to more specific sub-branches. It is possible that, even with Big Y data for all 12 men, some of them may sit on very isolated branches within the overall tree because they are only one of a few descendants who survive from that particular branch. In some cases, they may be the sole surviving member of a particular Gleeson branch. Only Big Y testing will help clarify this.

Prior to the overarching Gleeson ancestor (1100 AD), the North Tipperary Gleeson's shared a common ancestor (who had BY2852) with a group of neighbouring Carroll's, and before that they shared a common ancestor with a man whose descendants would later carry the names Bell, Phelps, McMahon & Prendergast (to whom he passed on Z16438). And earlier still, we shared a common ancestor who had Z16437 and his descendants include men called Miller, Treacy, McConnell, Hally, McCarthy & Cremen.

There is an interesting surname associated with  Branch F  (Carles) who tests positive for BY14197 but not the downstream SNP marker BY14189. I wonder if this man is a descendant of a Gleeson who emigrated to Spain some time after 1200 AD (possibly with The Wild Geese)? I will be making enquiries and will feed back in due course.

In the next post, I'll give a detailed description of the pdf document which includes all the data that went into creating MHT v4 and will explain the methodology and process of how the MHT was built.

Maurice Gleeson

May 2020