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A Predominantly Neolithic Origin for European Paternal Lineages
"This study examines the diversity of the paternally inherited Y chromosome, focusing on the commonest lineage in Europe. The distribution of this lineage, the diversity within it, and estimates of its age all suggest that it spread with farming from the Near East. Taken with evidence on the origins of other lineages, this indicates that most European Y chromosomes descend from Near Eastern farmers. In contrast, most maternal lineages descend from hunter-gatherers, suggesting a reproductive advantage for farming males over indigenous hunter-gatherer males during the cultural transition from hunting-gathering to farming."
A Set of Distinctive Marker Values Defines a Y-STR Signature for Gaelic Dalcassian Families
"Analysis of 25-marker short tandem repeat haplotypes in the Ysearch database reveals a distinctive Y-DNA signature that peaks in frequency in the Irish counties of Tipperary , Clare and Limerick. These counties were the hereditary homelands of the Dál gCais families, also called Dalcassian, septs descended from Cas, born CE 347, sixth in descent from Cormac Cas, King of Munster. Dalcassian surnames are more strongly represented with this signature than other surnames. A Y-STR signature for the northern Uí Néill lineages was previously identified. In the present paper, we present evidence for the signature of the Dál gCais, presently referred to as “Irish Type III."
A Y Chromosome Census of the British Isles
"To provide a more complete assessment of the paternal genetic history of the British Isles, we have compared the Y chromosome composition of multiple geographically distant British sample sets with collec- tions from Norway (two sites), Denmark, and Germany and with collections from central Ireland, represent- ing, respectively, the putative invading and the indige- nous populations. By analyzing 1772 Y chromosomes from 25 predominantly small urban locations, we found that different parts of the British Isles have sharply different paternal histories; the degree of population replacement and genetic continuity shows systematic variation across the sampled areas."
“Most heritable surnames, like Y chromosomes, are passed from father to son. These unique cultural markers of coancestry might therefore have a genetic correlate in shared Y chromosome types among men sharing surnames, although the link could be affected by mutation, multiple foundation for names, nonpaternity, and genetic drift. Here, we demonstrate through an analysis of 1,678 Y-chromosomal haplotypes within 40 British surnames a remarkably high degree of coancestry that generally increases as surnames become rarer. On average, the proportion of haplotypes lying within descent clusters is 62% but ranges from 0% to 87%. The shallow time depth of many descent clusters within names, the lack of a detectable effect of surname derivation on diversity, and simulations of surname descent suggest that genetic drift through variation in reproductive success is important in structuring haplotype diversity. Modern patterns therefore provide little reliable information about the original founders of surnames some 700 years ago. A comparative analysis of published data on Y diversity within Irish surnames demonstrates a relative lack of surname frequency dependence of coancestry, a difference probably mediated through distinct Irish and British demographic histories including even more marked genetic drift in Ireland.”
Geographic Patterns of Haplogroup R1b in the British Isles
"This study has provided a means linking DNA results to haplotypes and conclusions in Sykes’ book, “Blood of the Isles.” The study has confirmed Sykes’ interpretation of the data, and hopefully, provided a means for other researchers to further validate and extend his work. The study both confirmed some subclades identified by Sykes as well as identified some new subclades worthy of further research. Key subclades that the study posits and which are defined by Sykes include those of the Picts and the Dal Riada Celts."
The Advantages of a Dual DNA/Documentary Approach to Reconstruct the Family Trees of a Surname
"Family history research has traditionally been done primarily through a combination of oral and documentary research. Recently, the development of Y-chromosome DNA tests has created a process so that men, sharing the same surname, can verify whether their previous documentary research has assigned them to the correct tree or direct their future research towards documenting it. This article shows how integrating a collection of surname-defined Y-chromosome DNA results produces advantages for a traditional global surname documentary research project and outlines a methodology for managing a dual approach project that combines DNA tests and documentary research where the primary aim is to reveal the origin(s) of the name."
Y-chromosomes and the Extent of Patrilineal Ancestry in Irish Surnames
“Ireland has one of the oldest systems of patrilineal hereditary surnames in the world. Using the paternal co-inheritance of Y-chromosome DNA and Irish surnames, we examined the extent to which modern surname groups share a common male-line ancestor and the general applicability of Y-chromosomes in uncovering surname origins and histories. DNA samples were collected from 1,125 men, bearing 43 different surnames, and each was genotyped for 17 Y-chromosome short tandem repeat (STR) loci. A highly significant proportion of the observed Y-chromosome diversity was found between surnames demonstrating their demarcation of real and recent patrilineal kinship. On average, a man has a 30-fold increased chance of sharing a 17 STR Y-chromosome haplotype with another man of the same surname but the extent of congruence between the surname and haplotype varies widely between surnames and we attributed this to differences in the number of early founders. Some surnames such as O'Sullivan and Ryan have a single major ancestor, whereas others like Murphy and Kelly have numerous founders probably explaining their high frequency today. Notwithstanding differences in their early origins, all surnames have been extensively affected by later male introgession. None examined showed more than about half of current bearers still descended from one original founder indicating dynamic and continuously evolving kinship groupings. Precisely because of this otherwise cryptic complexity there is a substantial role for the Y-chromosome and a molecular genealogical approach to complement and expand existing sources.”