CLUSTER 1 is shaded in tan and includes twenty-four samples. Shown on the first line are the cluster modal values—those that occur most often at a given marker within the cluster. Ancestors of these lines were first of record in Donaghedy Parish, County Tyrone; Desertegny Parish, County Donegal; Killard Parish, County Clare; unspecified localities in Counties Sligo and Longford, and in Virginia and Kentucky, USA. Of those tested at 37 or more markers, most are within three steps of the modal, or most frequently occurring, values--close enough for a 50% probability that their most recent common ancestor lived within the past eight generations. Two others, with matches within four or five steps, and three tested at only 12 markers, are still close enough to the cluster mode to be descended from a common ancestor who bore the name Ó Duibhín at some point since it was first recorded, in Donaghedy in the 1400s.

ATLANTIC MODAL HAPLOTYPE. Twenty-one of the twenty-four Cluster 1 samples also show the defining values for the six markers that define the Atlantic Modal Haplotype (AMH), the most common six-marker DNA haplotype along the Atlantic coast of Europe. It was thought to be of Paleolithic or pre-Ice Age origin, and includes most male Basques, as well as a majority of Irish males with Gaelic surnames. However, the most recent studies indicate a later origin and its migration into Europe from the Near East as the glaciers melted back.  An early divergence of Clusters 2 and 3 from Cluster 1 is indicated by similar mutations in the two latter clusters from one of the six markers that define the Atlantic Modal Haplogroup, but most of the Cluster 1 samples retain the AMH motif.

CLUSTER 2, shaded in green, has nine samples, all tested at 37 markers. Although probably descended from a common Devine ancestor some centuries back, for the most part they are not closely related. However, two samples, from lines first of record in the adjoining counties of Roscommon, in 1805, and Galway, in 1826 at Loughrea, although they differ at seven markers, are within three and four steps each of a hypothesized “in-between” common ancestor, close enough to have inherited their surname from a considerably more recent common ancestor. Further confirming a closer relationship than the first 37 markers suggest, the three samples tested at 67 markers (DEV 24. DEV 57 and DEV 58) added at most one additional mutation to their five, seven or eight-step distances from the modal values at 37 markers.