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Thursday, November 10, 2016

How British are you really? A Look at AncestryDNA


An blog post from Ancestry.com caught my eye again. It was entitled, "The British Are Less British Than We Think." The post refers to "AncestryDNA's new study" and goes on to include the above graphic and other information about the makeup of the British population. As a note, the graphic has the notation on the bottom that says, "Values are rounded. For full details see ancstry.me/UKDNAStudy." The web address given is non-existent. So I began the process of looking into the substance of the "study."

It turns out the topic of advertising by Ancestry.com is related to a post I wrote recently entitled, "Does your last name indicate royal blood?" I don't really have anything against either Ancestry.com or DNA testing in this context, but I do have some real questions about the advertising when the topics gets into the are of genealogy and ancestry in general and are not completely accurate.

I started with a news article in The Telegraph on July 28, 2015 entitled, "How British are you? Mapped: DNA testing shows the most Anglo-Saxon Regions in UK." The Telegraph article states, "The study, by AncestryDNA, looked into 500 years of the UK’s ethnic make-up, tracking 26 global regions to home shores." However, since the link on the post from Ancestry.com and the news post do not have a link to the study, I needed to dig a little deeper. I also found another Ancestry.com blog post from September 19, 2016, entitled, "How British are you? DNA study reveals UK's ethnic diversity."

I found an earlier Ancestry.com blog post from April 21, 2015 entitled, "Recent University of Oxford study sheds light on estimating Great Britain ehnicity." Quoting from this post,
For every AncestryDNA customer, we estimate the ethnic origins of their ancestors from their DNA sample—what we call a “genetic ethnicity estimate.” AncestryDNA customers can currently trace their ancestral origins to specific parts of the world, including 26 regions across Europe, Africa, Asia, and the Americas. Since the AncestryDNA science team is always on the lookout for ways to improve our genetic ethnicity estimates, we were excited about the appearance of a new scientific article in the journal Nature, “The fine-scale genetic structure of the British population.” How well do their findings match up with patterns of genetic ethnicity for individuals with British ancestry at AncestryDNA?
It looks to me like the Ancestry study may have originated from an article in the journal, Nature, dated 18 March 2015 entitled, "The fine-scale genetic structure of the British population." Quoting from the Abstract of the Nature article,
Fine-scale genetic variation between human populations is interesting as a signature of historical demographic events and because of its potential for confounding disease studies. We use haplotype-based statistical methods to analyse genome-wide single nucleotide polymorphism (SNP) data from a carefully chosen geographically diverse sample of 2,039 individuals from the United Kingdom. This reveals a rich and detailed pattern of genetic differentiation with remarkable concordance between genetic clusters and geography. The regional genetic differentiation and differing patterns of shared ancestry with 6,209 individuals from across Europe carry clear signals of historical demographic events. We estimate the genetic contribution to southeastern England from Anglo-Saxon migrations to be under half, and identify the regions not carrying genetic material from these migrations. We suggest significant pre-Roman but post-Mesolithic movement into southeastern England from continental Europe, and show that in non-Saxon parts of the United Kingdom, there exist genetically differentiated subgroups rather than a general ‘Celtic’ population.
There is no indication that Ancestry.com participated in this study which involved researchers from several different universities around the world, not just Oxford. The study cited is interesting, but it is not clear how any individual's DNA test with Ancestry.com would correlate to the findings in the Nature article.

Yet another article on Metro.co.uk, from July 28, 2016 entitled, "It's more than likely you're not 'ethnically British" again quotes "A massive study conducted by Ancestry." So where is the Ancestry.com study?

It appears that the "study" referred to is really the earlier study cited in the Nature article. See another article from TheGuardian.com dated March 18, 2015, entitled "Genetic study reveals 30% of white British DNA has German ancestry." Quoting from The Guardian article,
Prof Peter Donnelly, director of the Wellcome Trust Centre for Human Genetics at the University of Oxford, who co-led the research, said: “It has long been known that human populations differ genetically, but never before have we been able to observe such exquisite and fascinating detail.” 
The study found that people’s ancestral contributions varied considerably across Britain, with people from areas of Wales, Scotland and Northern Ireland emerging as separate genetic clusters, providing a scientific basis to the idea of regional identity for the first time.
I suggest you may want to take the advertising done about DNA testing with a little more than a grain of salt.

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