Africans in Yorkshire? The deepest-rooting clade of the Y phylogeny within an English genealogy

Aims

To explore whether the presence of African ancestry can be genetically traced in people regarded as ‘indigenous’ British in the United Kingdom.

Methodology

DNA was taken from males in the UK and the USA: using electoral rolls, a random sample of R-surnamed males were selected. Each person completed a questionnaire with the aim of excluding close relatives, to prevent their similar genetic profile from skewing the results. A total of 421 British males were recruited, each describing themselves as British, with paternal grandfathers born in Britain. The DNA samples were subject to genetic testing.

One male was identified who shared genetic markers with Western African populations [the significance of which is outlined below], despite no obvious physical or historic indicators of African heritage. A further 18 males with the same surname were recruited. This name was derived from a specific settlement in east Yorkshire, and a significant number of bearers are still found in the area. Genealogical research was carried out on 7 members of this group who were found to share the same genetic markers as the first male, to assess possible familial relationships.

Key issues

The markers, which are found in only 5.4% of the African population today, have previously been detected globally in just 7 individuals described as being from non-African indigenous populations. Notably, the most common markers found in genetic studies of Africans were not detected in the sample, despite statistically being more likely to appear if there had been substantial African migration in the past, suggesting only a small historical presence.

The existence of a male from the UK sample with such markers has proved the first positive identification of African ancestry in ‘indigenous’ Western European populations, although their historical presence has been known in Britain from Roman times. By comparing the samples with 7 males who also carried the marker, the research team estimated that the relevant chromosome has been present since at least the mid-18th century, and possibly earlier. This conclusion was based on genealogical and genetic research which traced a shared heritage occurring before 1734. It was not possible to estimate whether the marker was introduced a short time prior to that date or significantly earlier.

Conclusions

The study demonstrates that African ancestry is present among ‘indigenous’ British people, but the existence of an unusual genetic marker shows that predicting African origin by using the most common markers associated with African lineages must be advanced with caution. The authors speculate that survey bias of DNA sampling may be one cause of low detection rates of African ancestry among previous studies.