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

Sapienza University of Rome, Roma, Latium, Italy
European Journal of HumanGenetics (Impact Factor: 4.35). 04/2007; 15(3):288-93. DOI: 10.1038/sj.ejhg.5201771
Source: PubMed


The presence of Africans in Britain has been recorded since Roman times, but has left no apparent genetic trace among modern inhabitants. Y chromosomes belonging to the deepest-rooting clade of the Y phylogeny, haplogroup (hg) A, are regarded as African-specific, and no examples have been reported from Britain or elsewhere in Western Europe. We describe the presence of an hgA1 chromosome in an indigenous British male; comparison with African examples suggests a Western African origin. Seven out of 18 men carrying the same rare east-Yorkshire surname as the original male also carry hgA1 chromosomes, and documentary research resolves them into two genealogies with most-recent-common-ancestors living in Yorkshire in the late 18th century. Analysis using 77 Y-short tandem repeats (STRs) is consistent with coalescence a few generations earlier. Our findings represent the first genetic evidence of Africans among 'indigenous' British, and emphasize the complexity of human migration history as well as the pitfalls of assigning geographical origin from Y-chromosomal haplotypes.

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    • "Although mitochondrial DNA (mtDNA) and Y-chromosome markers routinely demonstrate informative geographic differentiation, they are less suited to analyzing individuals with admixed parentage and genomic backgrounds (i.e., when recent gene flow has occurred), leading to possible classification errors [12]. For this reason, autosomal SNPs are much less prone to the risk of misinterpretation that can occur when finding an atypical patri-or matri-lineage, unrepresentative of the overall ancestry of an individual [13] [14] [15]. Therefore, forensic analysis has adopted a range of autosomal SNP sets that can be used as a stand-alone tool or to provide additional ancestry data complementary to uniparental variation [11,14,16–21]. "
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    • "The 448 MSY sequences belong to 440 different SNP haplotypes, identical cases being found in eight pairs of individuals. One pair, within hg A1, belongs to a previously reported deep-rooting English pedigree (King et al. 2007), and the males are separated by just 13 generations. The remaining seven pairs are apparently unrelated, but each pair belongs to a single population – there are "
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    ABSTRACT: Many studies of human populations have used the male-specific region of the Y chromosome (MSY) as a marker, but MSY sequence variants have traditionally been subject to ascertainment bias. Also, dating of haplogroups has relied on Y-specific short tandem repeats (STRs), involving problems of mutation rate choice, and possible long-term mutation saturation. Next-generation sequencing can ascertain single nucleotide polymorphisms (SNPs) in an unbiased way, leading to phylogenies in which branch-lengths are proportional to time, and allowing the times-to-most-recent-common-ancestor (TMRCAs) of nodes to be estimated directly. Here we describe the sequencing of 3.7 Mb of MSY in each of 448 human males at a mean coverage of 51 ×, yielding 13,261 high-confidence SNPs, 65.9% of which are previously unreported. The resulting phylogeny covers the majority of the known clades, provides date estimates of nodes, and constitutes a robust evolutionary framework for analysing the history of other classes of mutation. Different clades within the tree show subtle but significant differences in branch lengths to the root. We also apply a set of 23 Y-STRs to the same samples, allowing SNP- and STR-based diversity and TMRCA estimates to be systematically compared. Ongoing purifying selection is suggested by our analysis of the phylogenetic distribution of non-synonymous variants in 15 MSY single-copy genes.
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    • "relationships, the gene flow from Africa to Western Europe could be dated to before 1700 (de Knijff, 2007; King et al., 2007b), indicating the complexity of gene flow events even before the Industrial Revolution in Western Europe at the beginning of the 19 th century. Another recent Y-chromosomal study found evidence for a past gene-flow event from Northern France to Flanders (Larmuseau et al., 2012b). "
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