January 13, 2008

DNA unveils African ancestry among British

Africans have lived in Britain at various times since the age of the Roman Empire. However, it is believed that no genetic trace has remained among modern inhabitants. A special kind of Y chromosome type, the deepest-rooting clade of the Y phylogeny is known as the haplogroup (hg) A has never been found among populations that are original from Western Europe, including Britain. This haplogroup is known to be African-specific. Last year, scientists from the Department of Genetics at the University of Leicester described the presence of an hgA1 chromosome in a British male who is clearly indigenous (original from) the British region of Yorkshire. Further comparisons of this Y-chromosome with several African individuals suggest a Western African origin.

The researchers investigated the area and found that of 18 men carrying the same rare east-Yorkshire surname, seven also carry hgA1 chromosomes. By analyzing the genealogy of these persons they concluded that their ancestors lived in Yorkshire in the late 18th century.

The genealogical investigations were corroborated by genetic testing using 77 Y-short tandem repeats (STRs) and is consistent with an ancestor from few generations earlier. This is the first time that scientists find genetic evidence of Africans among 'indigenous' British.

The authors of the study say that this results make clearer that migrations and evolution of current human populations is very complex. Also, they warned that these data show that inferring geographical conclusions from Y-chromosomal haplotypes a priori can be unreliable.
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