Robinson Genealogy

Phylogenealogy is the study of lines of descent of groups of men using the procedures of genetic genealogy, which include genetics, surname studies, history and social analysis.
This paper uses spatial and temporal variation in the subclade distribution of the dominant Irish/British haplogroup R1b-L21 to describe population changes in Britain and Ireland over a period of 4500 years from the early Bronze Age until the present. The main focus is on the initial spread of L21-bearing populations from south-west Britain as part of the Beaker Atlantic culture, and on a major redistribution of the haplogroup that took place in Ireland and Scotland from about 100 BC.
The distributional evidence for a British origin for L21 around 2500 BC is compelling. Most likely the mutation originated in the large Beaker colony in south-west Britain, where many old lineages still survive. From that spread point it was carried rapidly by sea into north-west France, Ireland, north-west Spain and the Middle Rhine, which today have a high incidence of L21, and into Northern England and Scotland. Of about 45 known early Bronze branches or subclades of L21, almost all are found in Britain or in the English-speaking Diaspora. We are able to identify most of the larger subclades of L21 as ‘Atlantic’—spread throughout the Atlantic Beaker range with a distinct presence in Cornwall-Devon in the early Bronze. Continental R-L21 has origins in small random samples from the extensive English distribution. While many studies have tried to identify continental contributions to Isles populations, here we suggest that the reverse was much greater, at least in the early Bronze Age.
The global distribution of L21 subclades is almost exactly Pareto, showing an entirely random expansion from an initial point of time, however that point is much later than the early Bronze. Around 100 BC a second major R-L21 expansion from a severe bottleneck was initiated in Ireland and Scotland, when a dozen residual ‘deep’ sub-branches sprang to life and came to dominate L21. This is consistent with a collapse in the effective population of Ireland, followed by a rapid expansion. The limited evidence suggests that a severe weather event, famine and/or epidemic occurred around this time. The strongly patrilineal nature of insular Celtic society helped to keep male lines culturally intact, so that these emergent deep subclades can still be identified with Irish clans to some extent.
Around 90 per cent of R-L21 individuals in Scandinavia have paternal-line relatives in Ireland and Scotland dating to Viking times. The distribution is random and involves small numbers and distinct lines, suggesting that some of these were taken to Scandinavia as prisoners and slaves.
The Great Migration of millions of people from Ireland and Scotland to North America in relatively modern times was so substantial that no founder effects can be discerned and the New World has acted as a growth matrix extending and preserving the pre-existing R-L21 distribution.
This paper introduces several ‘skyline’ methods to trace the development over time of the subclade distribution of L21. These show that the distribution in England has not changed a great deal since the Bronze Age, in stark contrast to the situation in Ireland and Scotland. England and the Continent now make a much smaller contribution to R-L21 than in the past, probably stemming from Roman and Germanic expansion that pushed L21-bearing populations westward.