Saturday, 29 July 2017

Comparing match tallies for family members with Family Tree DNA's Family Finder test

I've taken a look at the total number of matches for all my family members who have taken a Family Finder test at Family Tree DNA. I've also done a comparison with the data I extracted on 26th May 2016 just before Family Tree DNA updated their matching algorithms. The results are shown in the table below. Note that I have excluded immediate family members from the totals.

Relation Number of matches
 28 July 2017
Number of matches
 26 May 2016
% increase
Debbie 1217 592 51%
Debbie's dad 1344 643 52%
Debbie's mum 1038 495 52%
Debbie's husband 905 443 51%
Debbie's eldest son 1138 542 52%

If my matches are representative of the wider Family Finder database then there has been over a 50% increase in the size of the database in the last 14 months.

I've also looked at the number of matches I share with my parents and taken stock of the number of matches which don't match either parent.

I share 501 matches with my dad. Of these, 320 were assigned to the paternal side with FTDNA's Family Matching tool. The remaining 181 matches were in common with my dad but did not meet the threshold for Family Matching.

I share 402 matches with my mum. Of these, 276 were assigned to the maternal side with the Family Matching tool. The remaining 126 matches did not meet the threshold for Family Matching.

I therefore have a total of 903 matches which match my mum or my dad. However, this means that 314 of my 1217 matches (26%) do not appear in the match lists of either of my parents.

All the matches that don't match my parents have a longest segment under 15 cMs. This is the breakdown.

Longest block  Number
10-14 cMs 28
7-9 cMs 286

The last time I did a comparison of parent and child matches I found that 23% of my matches did not match either of my parents.

These matches are either false positives or false negatives but without further investigation it is not possible to tell.

Have you tested both of your parents at Family Tree DNA? What are your statistics?

Friday, 28 July 2017

DNA surprises

In all my genetic genealogy talks I always warn people to be prepared for the unexpected when taking a DNA test. DNA is a very powerful tool for the genealogist but it can also uncover family secrets and reveal close relations that we didn't know existed. Furthermore, we don't always get the answer we expected. As Bennett Greenspan of Family Tree DNA often says in his talks: "If you don't want to know the answer, don't ask the question". For some people DNA can completely overturn their concept of identity and they discover that they are not who they thought they were.

Sometimes DNA can reveal the most incredible stories that are stranger than anything in fiction. One such story has just been published this week in The Washington Post. The article focuses on a number of surprise findings from DNA testing but tells in detail the story of Alice Collins Plebuch who took a DNA test with AncestryDNA which was to change her life forever. The article is is a long read but a very worthwhile investment of your time.  The journalist Libby Copeland is to be congratulated for her sensitive coverage of this story and her meticulous attention to detail. You can read the article by clicking on this link.

We have in fact known about this story in the genetic genealogy community for several years now, but this is the first time it has been picked up by the mainstream media. If you want some further background information check out this article on CeCe Moore's blog where the story was first revealed. There is an additional perspective in this blog post. Both of these blog posts also have additional photographs that weren't in The Washington Post article, but don't read the blog posts until you've read the article.

Wednesday, 26 July 2017

Parent and child comparisons at MyHeritage DNA

I recently transferred my parents' data to the MyHeritage DNA database and I thought it would be an interesting exercise to compare their matches and admixture reports with my own. I transferred my AncestryDNA v1 raw data to MyHeritage and my parents' Family Finder raw data from Family Tree DNA. All three tests were done on the same Illumina OmniExpress chip so there should be an almost complete overlap of SNPs.

MyHeritage are the newest entrant into the genetic genealogy market. They launched their autosomal test in November 2016. If you've tested with AncestryDNA, Family Tree DNA or 23andMe it is currently possible to do a free transfer to MyHeritage. It is not clear if the transfer will be free in the long term so do take advantage while you have the chance.

While the MyHeritage database still has a long way to go to catch up with the other companies there are already early reports of DNA success stories. MyHeritage benefits from a website which is available in many different languages, and they are therefore likely to attract customers who will not be found in any of the other databases.

DNA matches
MyHeritage currently provide information about the amount of DNA shared (measured in centiMorgans), the number of shared segments, and the size of the largest segment. A chromosome browser is not provided though this feature is reportedly in development. It is also not yet possible to download a list of your matches, but hopefully this will be possible in future.

One of the most useful features of the MyHeritage matches feature is that there are country flags against the names of your matches. This allows you to focus on the matches who live in the countries where you are mostly likely to share recent genealogical ancestors.

My dad currently has 59 matches at MyHeritage (excluding me as his daughter). Most of his matches are in America but he has four matches with people from Great Britain, three from Sweden, and one each from the Czech Republic, Canada and Norway.

My mum has 20 matches at MyHeritage (excluding me as her daughter). Again the matches are predominantly with Americans but she has two matches with people from Great Britain and one with an Australian.

I have 24 matches at MyHeritage (excluding my parents). I have one match each from Luxembourg, Great Britain, Australia and Ireland. The rest of my matches are in America.

MyHeritage have a nice Shared DNA Matches feature which not only allows you to see which matches you have in common but also provides relationship predictions and the amount of shared DNA for both matches side by side. This is what the Shared DNA Matches page looks like for me and my mum.

I share two of my 24 matches with my mum and six matches with my dad. However this means that 17 of my 24 matches (71%) do not match either of my parents. These matches are either false positives or false negatives, but without further investigation it's not possible to tell.

I don't recognise any of the names in the match lists and it seems to me that, even if the matches are real, the relationship predictions are overly optimistic. Some of the matches are predicted to be second to fourth cousins, and even the most distant matches are predicted to be third to sixth cousins. However, I do not have any ancestors who emigrated to countries like Sweden, Norway and the Czech Republic. I also don't have any ancestors who emigrated to America. I do have a few cousins in America through a collateral line but I know them all by name. The Americans on my match list are likely to be very distant cousins, if they are related to me at all. Of the matches that I share with my parents all eight of them are in the US.

Clearly MyHeritage need to do some work on the matching algorithms, and I'm sure we will see some improvements in future. For the moment it doesn't seem worth investing too much time in researching these matches.

Comparing admixture percentages
In addition to cousin matching, the MyHeritage test also includes a free admixture report which they call an Ethnicity Estimate. Results are compared with 42 reference populations around the world, and there are plans to add further populations in the future. MyHeritage do not state what time depth their test is designed to cover.

Here are the details of my dad's genealogical ancestry:
  • Four grandparents born in England: Bristol, Gloucestershire, London (x2).
  • Eight great-grandparents born in England: Bristol (x2), Devon, Essex, Gloucestershire, Hertfordshire, London (x2).
  • Fifteen great-great grandparents born in England: Devon (x2), Bristol, Essex, Gloucestershire, Hertfordshire (x 2), London. One great-great grandparent born in Scotland (location not known). The birthplace of seven of his English great-great-grandparents is unknown. Four were probably born in Bristol or in a nearby county. Three were Londoners who could have moved to London from anywhere in England. 
Here are my dad's admixture percentages from MyHeritage.

Here are the details of my mum's genealogical ancestry:
  • Four grandparents born in England: London (x2), Hampshire (x2).
  • Eight great-grandparents born in England: Berkshire, Hampshire, London (x3), Somerset, Wiltshire. The birthplace of one great-grandparent is not known but he was probably born in London.
  • One great-great-grandparent born in County Kerry, Ireland. Fifteen great-great-grandparents born in England: Bedfordshire, Berkshire (x2), Gloucestershire, Hampshire (x2), Hertfordshire, London (x2), Somerset (x2), Wiltshire. The birthplace of three of her English great-great-grandparents is unknown. One was probably born in Hampshire. The other two were probably Londoners who could have come from anywhere in the country.
Here are my mum's admixture percentages from MyHeritage:
Here are my admixture percentages from MyHeritage.
It's good to see that MyHeritage are at least trying to produce regional distributions within the British Isles, even though the results are somewhat off the mark. It's interesting to see that my parents come out with such very different results, despite the fact that they both have predominantly English ancestry. We have no Italian ancestry and the Italian component in the MyHeritage test does not show up in our results in tests with any other company. The admixture reports will no doubt be refined in future as the methodology improves and more reference datasets are added.

Further reading
Related blog posts

Wednesday, 19 July 2017

The end of the road for BritainsDNA and myDNAGlobal

I wrote back in May last year that the BritainsDNA family of companies, which includes ScotlandsDNA, IrelandsDNA, CymruDNAWales and YorkshiresDNA, had been rebranded under the new name of MyDNAglobal after the company was taken over by Source BioScience.

On checking the MyDNAglobal website today I discovered that the company is no longer taking orders. The following notice now appears on the website
Dear Customers 
It is with regret that effective from 3rd July 2017 MyDNA.global will no longer be accepting new orders. 
Whilst we have enjoyed offering this individual service it is unfortunately not something we are able to provide going forwards. 
All existing orders will be honoured – if you have recently purchased a test and have yet to return your sample please do so by 31 August 2017 so we can process your results.  
Unfortunately we cannot guarantee that samples received after 31 August 2017 will be processed. 
For those customers who have already received their results these will be available to you via our website until 31 August 2018, after which they will no longer be available. 
If you have any queries please email our support team: support@myDNA.global. 
Thank you for your custom.
If you've tested with any of these companies I would suggest that you download all your data while you have the chance.

Update
For further information on the demise of BritainsDNA and background information on Source Bioscience see the article by Ewan Lamb BritainsDNA - a thing of the past.