Welcome! 

The Diamond of Northern Ireland study was spun out of the broad Diamond surname project 10.22.2015 where it is known as the A12 lineage. O’Diomhain and A12 are one and the same.

The broad Diamond and surname variant study began in 2003 with the goal of discovering and defining yDNA signature of each of the American Colonial D*mond families. That quickly evolved to include lineages worldwide and resulted in linking lineage cousins to, in many cases, their ancestral roots. As of 2015 there are twenty-seven distinct yDNA family lineage signatures identified worldwide.

Diamond-Dimond in Northern Ireland and Ireland

There are to date 7 distinct Diamond-Dimond lineages, as defined by yDNA,  in Northern Ireland and Ireland.

Word of caution; if you have not tested do *NOT* assume or speculate as to which lineage from the following that you descend from. These are proven *biologic* lineages. Remember that biology does not automatically equate to *family*. DNA studies have significant single digit numbers of non-paternity events and adoptions. It is not unheard of to be a full member of a family and not be a biologic member. 

This project is specific to, and focused on, descendants of the O’Diomhain lineage. Lineage means that descendants share a common paternal ancestor at some unknown distant point in time. 

The project will not exclude any other Diamond-Dimond lineage whose root is Northern Ireland though they are not O’Diomhain. They their data will be grouped accordingly and their summaries included under ‘result’s tab. 

At this time there is one other biologic line confirmed to be of or came to the area. These are descendants of John Diamond of County Londonderry. A third yDNA defined lineage, that of Patrick Dimond, an eighteenth century migrant to North Carolina Province in what was to become the US claims to have come from the area but this remains unproven. Their yDNA signature has to date not been found in Northern Ireland. This does not make untrue just not a certainty. 

There are four other Diamond-Dimond lineages associated with Ireland to date and they are to the south in Counties Mayo and Sligo.

How there came to be so many genetically distinct Diamond-Dimond yDNA lines on the island is an interesting and open question. There is, however, no doubt that the oldest is the O’Diomhain of Derry and Antrim. They are the focus of this study project. 

O’Diomhain

Sept to Clan O’Cahan 

County’s Derry and Antrim Northern Ireland

The lineage is deeply rooted in Counties Londonderry and Antrim, Northern Ireland along the Lower Bann River. Once O’Diomhain the spellings are now Diamond and Dimond. The Dimond/Diamonds were an erenagh family of Kilrea, which means the family owned the land that was used for the place of worship and generally provided those who ministered there. Erenagh is from the Gaelic 'ceann' meaning head, leading, principal; some use it to mean 'stewardship' or 'the keeper of'. The early Celtic church differed in structure from the rest of western Christianity in that it did not have dioceses. Instead, it was monastic, that is, each area was an independent church governed by an abbot and each parish had its own bishop elected from a local erenagh family.

The lineage can be defined by high resolution STR haplotype (111 markers) and by membership in Y haplogroup I-L126.