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A longfather of old

Martin

Using Tolkien's phrase, I learned of a 'longfather of old' today, which has left me a little stunned.

It seems that I share a significant chunk of DNA with a man buried in the west of Ireland, in a megalithic tomb, more than 5,500 years ago. I have a large amount of Irish ancestry, but had no idea that it went so very far back in time as that.

Parents

  • I have a question.

    My 23 and Me results said that my ancestry composition is:

    78.4% British and Irish

    19.9% French and German

    1.7% Northwest European

    but my Living DNA results are different, based on the download of my raw genetic data from 23 and Me:

    97.5% Britain and Ireland

    1.4% Northwest Germanic

    1.7% Northwest European

    I don't know which one is correct (and why they would differ)?

Reply

  • I have a question.

    My 23 and Me results said that my ancestry composition is:

    78.4% British and Irish

    19.9% French and German

    1.7% Northwest European

    but my Living DNA results are different, based on the download of my raw genetic data from 23 and Me:

    97.5% Britain and Ireland

    1.4% Northwest Germanic

    1.7% Northwest European

    I don't know which one is correct (and why they would differ)?

Children
  • in reply to Deleted User

    My 23andMe results are a bit different to the results of my uploaded 23andMe raw data to Living DNA too. 

    I am not particularly knowledgeable about the reasons for the differences. I understand from the DNA company websites that the reason for the difference is along the lines of CatWoman’s explanation, ie, reference sample size and area covered. 

    23andMe states that they calculate your ancestry by comparing your genome to the genomes of people whose ancestries they already know. Their datasets include genotypes from 14812 people who were chosen to reflect populations before travel and migration were common - at least 500 years ago, with 957 reference individuals of French, German, Belgian, Dutch and Swiss. British and Irish make up 1014.

    23andMe states that their datasets are comprised largely of their own customers datasets. I would expect that this would lead to differences between your results from the same DNA, but I think we need an expert to interpret likely accuracy.

    I see 23andMe allows you to manipulate the default confidence level in your downloaded raw data analysis from 50% to a conservative 90%.

    LivingDNA state that all family ancestry results, from any company, are estimates, and are based on comparing your DNA to a set of reference samples.

    The link gives information on testing from Ancestry UK. I am considering taking a new test with them as I already have some of my family ancestral tree completed, although it is mainly through the male line, thanks to a more unusual surname.

    www.ancestry.co.uk/.../estimates

  • in reply to Deleted User

    I think and others here are far more knowlegable than I, will be able to confirm or deny this, but it can depend on how large the samples used to arrive at the estimates are, obviously the larger the sample the more acurate the results are likely to be. DNA research is moving at such a pace that many studies aren't published before they're superceded by newer research. Some countries are better represented in genealogical research than others, America seems to be very well researched as so many Americans know their recent ancestry is from elsewhere usually of European decent. Some countries, I believe France is one of them outright bans this sort of genealogical research in the name of Fench unity and also against comercialisation of genetic material, a DNA test is usually only carried out in France if court ordered, like for a paternity test.

    According to My Heritage, I'm 87% Southern English, with 7% Iberian and the rest made up of random Northwestern European. My Mum, has no Iberian DNA and I can't find anyone on my dads side of the family going back nearly 200 years who seems to be a recent imigrant. It's confusing and not an easy search when one has a fairly common name and seems to have spent a large part of thier time in the East End of London, thats if I got that connection right and I'm not sure I did. Unless you can go and physically search archives, church records and make any sense of military ones which seem designed to obfuscate. It can be pretty difficult and not as many of them are digitised as you're led to believe, some of the digitised records are of poor quality and difficult to read, others may well be accurate, but what I wondered looking at mine, was how much of what my peasant ancestors mumbled at an educated registrar of priest was recorded properly? Some of it I can make out where the mistakes are as I know what the local accent was and the stresses on vowels were a bit different to "educated" English. For example I guessed where Teresa May grew up because I recognised some of her pronunciation, such as Mondee instead of Monday, that particular way of pronouncing "ay" as "ee" is quite common in parts of Oxfordshire and Berkshire.