DNA for genealogy: Where to test?

IMPORTANT: This is not a post about testing for paternity issues, etc.  The courts have very specific requirements for DNA testing to be used in legal hearings.  You can find out about that on the Get a DNA Test page of the government’s own website.

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Which companies offer autosomal DNA testing for genealogy?
Having spent the last few weeks introducing the topic of DNA testing for genealogy, the purpose of this post is to signpost you to the five main companies used for genetic genealogy testing by genealogists and family historians in the UK.  Other companies are available and if you come across them you can research and assess their benefits for yourself.  However from my knowledge, gained through personal experience and through membership of online discussion groups, these are the companies most genealogists currently use.  I have no connection with any of these companies other than as a user, and am receiving no benefit whatsoever for including any of them in this review.

If you’d like to take a DNA test to help with your family tree building, follow the links to each company, look at their websites including privacy statements and terms & conditions, and then make your decision.

You might also like to look at the following DNA Weekly Best Ancestry DNA Tests review, which is updated regularly.

I would also recommend joining an online discussion group, such as DNA Help for Genealogy on Facebook.  There, you’ll find people of all levels of understanding from complete beginner to advanced.  You can ask questions, including recommendations and preferences for the various testing companies as well as practical questions when your results are in.  Somewhere down the line you’ll find you can actually start to answer other people’s questions too. 🙂

Here are the five testing companies, linked to their websites:
Ancestry DNA
Family Tree DNA
Living DNA – UK based, partnered with FindMyPast
My Heritage DNA – my experience is that more European testers use this company
23 and Me

How do they differ?
I’ve put together this table showing features of each testing company that are considered important by genealogists.

Table showing features of five different DNA testing companies used by genealogists

Notes
When considering the differences between these five testing companies and the advantages or disadvantages of each it’s perhaps useful to bear in mind that two of the companies (Ancestry and MyHeritage) are primarily genealogy websites, providing tree-building, a huge number of record sets, and a DNA testing service that is increasingly dove-tailed into that.  One of the companies (Living DNA) has partnered exclusively with FindMyPast.  Together, these UK-focused companies have the potential to provide a similar ‘seamless’ service as for the previous two, with a lot of new developments in the pipeline.  The final two companies (Family Tree DNA or ‘FTDNA’ and 23andMe) are primarily DNA research and testing companies.  They have the facility for uploading or linking to family trees but have no record sets, etc that will help you to develop your trees.  However, their DNA features and tools are often more sophisticated.

Uploading to other sites: You will see that Ancestry and 23andMe do not permit uploads to their site, but the remaining three companies do.  Uploading will enable you to access the tester database but will not provide use of enhanced features of the test (e.g. Living’s 21 UK-based geographical origin locations feature).  Although uploading is free there will be a charge if you want to access additional tools.  If you’re looking for biological parents it will help you to have your data on all of these sites.

AutoCluster tool: This is a tool available on MyHeritage.  It groups together your DNA matches in colour-coded groups likely to be descended from the same common ancestor.

Ethnicities: A lot of people take a DNA test purely for the fun of seeing their ethnic origins breakdown.  Learning about your ethnicities is exciting but it’s only an estimate and still a work in progress.  From time to time as more people test or as algorithms are amended, your ethnicities estimate will change.

Chromosome browsers: This is a visual tool that enables you to see precisely where you and another person match.  You will be able to see which chromosomes, whereabouts on that chromosome, the length of segments and their start and end points.  It is really useful to have this information and once you’ve been able to allocate a segment to a specific common ancestor it will help with identifying whereabouts on your family tree new matches will connect.  I will do a post about this in autumn 2020.

Y-chromosomal and mitochondrial testing: This is covered in my previous blogpost on deep ancestral DNA testing.  You will see that of the companies included on the above table, only Family Tree DNA (FTDNA) offers testing for these types of DNA.  However, 23andMe and Living DNA provide Y-chromosome and mitochondrial haplogroups as part of the autosomal test.

Note about 23 and Me tests: Ancestry + Traits is the basic test, providing an insight into which of your traits (e.g. aversion to coriander, curly hair) can be traced to your ancestry.  Health + Ancestry test is more expensive, providing insights into your predisposition of developing certain health conditions.  It is not necessary for our family research purposes, but is there as an option should you want it.

GEDmatch: This is not a testing company, but a very useful website where you can upload your DNA test results regardless of which company you tested with.  It therefore provides you with a much wider pool of testers and potential DNA matches.  It is free to use although payment is required to access certain more advanced tools.  I will do a post about this in autumn 2020.

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This concludes my series of ‘introduction to DNA testing for genealogy’ posts.  I hope they have helped you to decide if DNA testing is for you and if so, what are the next steps you need to take to make it happen. Please note that every effort has been taken to ensure all the details provided are correct, but you should refer to the different companies’ websites before making any decisions.

We’ll now take a break from DNA testing but I do have more posts planned for the future that will help you to make practical use of your DNA results.  As mentioned above, these will include Chromosome browsers and GEDmatch, but a number of other DNA topics too.

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Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones. Click [here] to read all of them in order, or to dip in and out as you wish. You’ll also find lots of resources and useful links

DNA: Asking other family members to test

So far in this introduction to DNA for genealogy we’ve looked at what autosomal DNA is and how we use it in genealogical research, and we’ve looked at the very important issue of potentially unexpected results and the ethical considerations flowing from that. It was essential to cover the latter two issues before progressing to today’s topic: asking our nearest and dearest if they would be prepared to take a DNA test to help with our research.

A quick review of how we use autosomal DNA for genealogy
As previously discussed, the point of establishing how much of your autosomal DNA you share with a second cousin, fourth cousin, third cousin once removed, etc is not the joy of knowing how much DNA you share with this former stranger.  The point is that by finding someone you match at this estimated level you are being guided to the number of generations you need to go back to find your Most Recent Common Ancestor (MRCA). If the amount of shared autosomal DNA, expressed as ‘centiMorgans’ (cM) suggests you are roughly 3rd cousins, then you would expect to find your MRCA at roughly great great grandparent level.  As mentioned in previous posts, it may be one generation closer or one generation further back, but it will be thereabouts.  Armed with that information, you look at both your family trees to locate the common ancestor.  Then, having found your MRCA, and ensured all research is correct to that point on both trees:

  • you know your tree is correct to that point
  • you know you have a biological link to these ancestors (there are no events which would cause a break in the biological link)
  • should you come across another DNA cousin who matches the two of you, you have a pretty good idea where to look for this new match.

It isn’t always as straightforward as this.  You or your new cousins might not have got as far back as that in your tree building.  As mentioned in my previous post on unexpected results, one of you might have no tree at all, as a result of adoption or unknown paternity.  There are also other issues that might complicate this which I’ll cover in a later post.  But for now, at this introductory level, we’ll stick with a basic scenario with everything going smoothly.  The important point is that, knowing where you and your new cousins share common ancestry, you can start to allocate them to a particular branch of your tree, and work on the basis that other testers who also match the three of you will also link to you on that branch.  Bearing in mind that we each have sixteen great great grandparents and 32 GGG grandparents, this will save you a lot of unneccesary work.

Why would we ask another family member to test?
When we ask a specific, known family member to test, we use their results in the same way: It helps us to sort more distant common matches into specific lines on our own tree.  However, since these are our close family members, and since every one of them will have inherited some DNA from our common ancestors that we didn’t, their test results will extend our ‘reach’.  Exactly how they will do this depends on their precise relationship to us.

Essentially the rule is:

  • Your direct line (parents, grandparents, etc) will produce stronger, better, DNA matches but limiting to an increasingly specific part of your tree with each older generation.
  • Your own siblings will have inherited much of the same DNA as you, but also a lot of different DNA.  Although their results will be of no use at all in guiding you to a specific part of your tree (because you have the same parents, grandparents, etc), the parts of their DNA you didn’t inherit will effectively provide you with more DNA matches.
  • Sibling of previous generations (your mother’s brother, your grandfather’s sister, etc) will combine the benefits of the first two categories, but the results will be a bit weaker than testing your direct line – which of course is often no longer possible.

Let’s look at each type of relationship in more detail.

Sibling
If you have one or more full siblings, you know that all of your DNA and all of their DNA comes from the same two people: your mother and father.  However although like you, your sibling will have received half their DNA from your mother and half from your father, unless you are identical twins they will not have received exactly the same DNA as you did.  (Key point: don’t bother asking your identical twin to test)

I can illustrate all this with reference to my own brother.

In my first post about autosomal DNA we looked at the Shared centiMorgan Project.  Click the image below to see it full size on Blaine T Bettinger’s website.

This shows that the average shared DNA with a full sibling is 2613cM, but it could be anything between 1613 and 3488.  My brother and I share 2616cM.  This is what proves we are full siblings.  What interests me, though, is all the bits of his DNA that I don’t share: they are the reason I asked him to take a test.  Since we are clearly full siblings, anyone who shares DNA with him is also my blood relative even if we haven’t inherited any of the same DNA.  Therefore I can use my brother’s DNA results and the trees of his matches as an extension of my own, to confirm and develop my own tree.  Their Most Recent Common Ancestors are my Most Recent Common Ancestors too.  It’s just that we haven’t inherited the same DNA from those ancestors.

If this is new to you you’ll be surprised at how many people can share a decent amount of DNA with one sibling and none at all with another.  After each other, the top matches for both my brother and me on Ancestry are:
A with whom I share 189cM but my brother shares only 102cM
B with whom I share 144cM but my brother shares 153cM
After them our next highest matches are completely different.
C with whom I share 51cM doesn’t show as a match to my brother.  In fact C is our 4th cousin two times over – we share two sets of 3xG grandparents.
Looking at our matches on MyHeritage, four of my brother’s top ten matches (all of them cM matches in the 50s) do not match me at all.

You can see how my brother’s results give me more information and more clues about my own ancestry.  If you have more than one sibling and they are all happy to take a DNA test to help with your research, so much the better!

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While full siblings give you extra ‘horizontal’ reach, every other close family member will help you in a different way: they help narrow down to one part of your tree where you and any DNA cousin you share actually match.  Siblings won’t do this because in terms of your direct lineage, everything is identical.

Parent
There are two advantages to having a parent’s DNA results:

  • First, since we inherit 50% of our DNA from each parent, it follows that we have only 50% of the DNA of each one.  This means that your parents’ DNA is closer to previous generations and will include the other 50% that didn’t pass to you.  You might show as a second cousin once removed to a match but your parent will be a full second cousin.  Because of all this, they will have more and better matches, with more shared centiMorgans.  As an example, one of my DNA cousins currently has 321 matches on Ancestry at 4th cousin or closer, whereas her mother has 511.  If her father were also still alive and willing to test, and supposing he had a similar number of matches, that would effectively transform their daughter’s 321 matches into about 1000 better ones.
  • Second, even if only one parent tests this will help you to narrow down any future match by 50%.  If you have your mother’s test results and your new DNA cousin doesn’t match your mother then your shared common ancestors are on your father’s side.  This will help save you a lot of time searching for your connection.

Grandparent
If you’re lucky enough to have a grandparent who is able and willing to take a DNA test for you the same applies as for your parents.  Not only will their results narrow down any matches to a specific quarter of your tree, but their DNA will be even closer to previous generations.  You may match another tester at fourth cousin level, but your grandparent will be a second cousin twice removed – a much stronger and clearer DNA match.

Key point: it always makes sense to test the oldest generation

Aunt or uncle
If you’re able to test a sibling of either parent this will enable you to narrow down any shared matches to one side of your tree or the other, just as your own parent’s test results would.  However, bearing in mind that siblings don’t inherit exactly the same DNA, your aunt or uncle would also extend the reach of your parent’s results horizontally, in the same way that your own sibling would for you.

Your aunt or uncle who is the half-sibling of your parent
This will have the same effect as a grandparent.  Since only one of your grandparents is the parent of your half-aunt or half-uncle, anyone matching the two of you has to be from that specific grandparent’s line.  However, for reasons outlined above, if you had the option to test your half-aunt/uncle or the actual grandparent who is that person’s parent, you should choose the grandparent.  This would provide the same information to help you narrow down matches to a specific quarter of your tree, but their match would be closer to past generations and therefore better.

Half sibling 
Your own half sibling’s test results will help in the same way as your shared parent’s results.  They will help you to narrow down a match to either your maternal or your paternal line.  However, for reasons outlined above, if a parent is still available and willing to test, their results will be better for you.

Cousin
Your cousin, being the child of your parent’s full sibling, will help you to narrow down shared matches to one side of your tree. On the one hand, your own parent will give you better information.  On the other hand, since your cousin’s parent’s DNA will not be identical to your own parent’s, they might extend your reach horizontally on this line, just as your own sibling would.  Even better, though, to test your actual aunt or uncle.

Slightly more distant relations, e.g. second cousin
In reality, unless you have a very close extended family, you are unlikely to pay for your second cousin to take a DNA test.  However, they might have tested of their own volition, and in the absence of any of the above family members, a second cousin’s results can be very helpful in narrowing a match down to a specific quarter of your tree.  You and they are the great grandchildren of the same couple, therefore any other tester who matches the two of you will probably be further back along that same line. 

Key point: Your own son or daughter’s test results will not help you
Your own child’s test results will not add anything to your DNA research, since they have inherited only 50% of your DNA and are obviously one generation further removed from all your ancestors.  On the other hand if they are interested in their ancestry, your own test results will help them to narrow down to one or other side of their tree, just as your own parents would help you.

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If all this was new to you I hope, by now, you have a basic understanding of how DNA testing can enhance your family research.  If you’re interested in taking a test, my next post will provide an overview of the five main testing companies.  After that, there will be more to say, but we’ll take a break from DNA for a while.

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Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones. Click [here] to read all of them in order, or to dip in and out as you wish. You’ll also find lots of resources and useful links

DNA testing: Ethical considerations

In my last post we looked at the possibility of unexpected information when we receive the results of our autosomal DNA test, and the importance of being fully aware of this as a possibility before we consent or ask others to consent to the test.  We noted that ‘unexpected results’ might take the form of finding our own parentage or descent from recent generations is not supported by the DNA.  Alternatively, the results might show that we are most definitely biologically linked to our parents and grandparents, but that someone else is too – someone of whom we had no knowledge.

Both findings can be upsetting at least and devastating at worst.  As a member of online genealogy groups, I occasionally see posts from distressed group members, formerly so excited to receive their DNA results but now trying to come to terms with the fact that ‘Dad’ is not really father, or ‘Granddad’ is not really grandfather.  What I say is this: the man you knew as your Dad is still your Dad.  The Granddad who loved you is still your Granddad.  You were meant to have this connection, even if biologically he’s not part of you.  But now you have another ancestral line to research too – one that might reveal other fascinating stories and might help you feel ‘complete’, even answer some questions you had about yourself, like where your dimples or your violet-blue eyes came from.  We might even call it your ‘nature’ tree and your ‘nurture’ tree: both have made you who you are.

Again, through online genealogy groups, I know of group members experiencing conflict within their own families regarding digging up the past and poking about in people’s lives.  My view is that if this is a hobby you love and from which you derive much pleasure and mental stimulation, then you should do it, but it’s important to do so in a way that respects the feelings and sensitivities of those who wish you wouldn’t.  Although no skeletons have been revealed in my own DNA testing, my documentary research has uncovered stories that I simply couldn’t have shared with my parents and grandparents.  In some cases the difference in sensitivities might be a generational thing: certain things were not discussed, were considered shameful and kept secret.  In other cases it might simply be a question of proximity to the subject of the story: the great grandfather who died long before we were born was our own parent’s grandfather, and may have been much loved and best left that way.  How much more sensitive, then, if the story relates to an extra-marital affair, the proof of which is now before you in the form of a match at second cousin.  It’s simply a matter of being sensitive to the needs and sensibilities of others.

On the other hand, in the case of an extra-marital affair – an illegitimate or adopted child – there are the needs of that person to consider too.  I said in my last post that I will always do what I can to help a good DNA match to track down their parents.  In one case the biological father turned out to be a (deceased) cousin of one of my parents – although there were several brothers in the family and without further DNA testing I can’t say which one.  In those circumstances I had no qualms about making available the name of the family to my ‘new’ second cousin.  It would in any case be available via other online trees.  It’s true that in those ‘Long Lost Family’ programmes on TV there is generally a happy ending of sorts.  Indeed, an acquaintance of mine was so happy to learn that a long-ago pre-marital relationship of her late father had produced a child, now to be welcomed into the family as a long-lost half-brother, that she circulated an email to everyone on her contacts list, with photographs of the new family group, highlighting the very strong family resemblance.

However, the reality isn’t always like that.  A biological mother who put her child up for adoption might have spent fifty years thinking of her lost child but it may be a secret she fully intends to take to her grave.  She may be ashamed to admit the truth to her family.  I know someone who, a few days after his mother’s death, discovered the birth certificate of his long-ago adopted half-sister in his mother’s handbag.  In life, she had never had the courage to tell her children, yet clearly that firstborn child had never been far from her thoughts, and she wanted her remaining children to know.

I’m aware that I’m writing about all this from the perspective of someone who has not experienced it.  For someone who is that child or perhaps their half-sibling, the reality is very different.  No one should feel like a ‘dirty little secret’.  This article, although US-based, deals with the issue from the viewpoint of test-takers who have learned they are the result of an affair, rape or sperm donation, and provides some information about secret groups on Facebook where those affected can gather and speak to others in their position.

You and I may not agree on the best way forward in these sensitive situations.  There is, indeed, no agreed ‘Code of Practice’ for how to proceed from this point forwards.  Since 2015 a set of Genetic Genealogy Standards have been in place, but these are intended to provide ethical and usage standards for the genealogical community to follow when purchasing, recommending, sharing, or writing about the results of DNA testing for ancestry.  They don’t specifically relate to how, or whether, to tell Aunt Maggie her late husband fathered a child ten years into their marriage.

Clearly, then, the implications of DNA testing are wide.  Whether we test only ourselves or a handful of other consenting family members too, the fact remains that the results – in terms of what is revealed through the people we match with – will reveal information not only about ourselves but could impact on other close family members who have not tested – who possibly would not have consented to a test even if we had asked them.  Nevertheless, the genie is now out of the bottle: as of 2018, more than 26 million worldwide had taken such a test and it is estimated that by the end of next year the figure may be approaching 100 million.

Our responsibility is to recognise all of the above, and to proceed with integrity and discretion.  It’s likely that we will all have different approaches to these ethical issues.  Yours may not be the same as mine, and in any case it makes sense to adjust our approach depending on the people involved.  But with all this in mind, I’ve put together this checkpoint of ethical considerations:

  • We must respect privacy and confidentiality.
  • We must recognise that not everyone will respond to stories with the same outlook as our own, and we must be sensitive to the specific needs and feelings of each.
  • Before asking another family member to test for us, we must ensure they are fully aware of the possibility of unexpected results.  (I’ll explain in my next post why it can be useful to ask family members to test.)  At the time of asking them to do so we should clarify if they would want to be informed of any unexpected results, and undertake to respect their wishes.
  • Even if the key players in this scenario are now deceased, their actions may have an impact on others who are still living.  Their needs must be taken into consideration too.
  • If we decide to tell others of unexpected findings – such as the discovery of a child or half-sibling, we must be discrete, operate on a need-to-know basis, and leave it to the person or people involved to decide if this new information is to be shared more widely.
  • We should let sleeping dogs lie: If I see evidence of misattributed parentage in another person’s tree (and there is definitely one who matches a person whose DNA I manage) I would never tell that person unless they got in touch to investigate the connection.

If you have never considered DNA testing to help with your family research, I hope this post and the previous two have helped you to think through the issues and decide if you want to do so.  The final two posts in this ‘whirlwind introduction’ to DNA testing will look at the benefits of asking other family members to test, and finally at which companies provide DNA testing for genealogy.

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Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones. Click [here] to read all of them in order, or to dip in and out as you wish. You’ll also find lots of resources and useful links

DNA: Unexpected test results

In my last post we looked at autosomal DNA – what it is, and a little about how we can use the results of a DNA test to help us progress our family trees.  Before going any further let’s consider an important issue that should be borne in mind from the outset when deciding whether to test.

The fact is that DNA testing can reveal unexpected, uncomfortable information.  It is statistically unlikely, but we should be aware of the possibility when taking a test, and be prepared to deal with the consequences.  Our family trees may be meticulously researched, fastidiously sourced and referenced and the very model of genealogical good practice.  But DNA test results may reveal what birth registration and baptismal documents cannot.

These unexpected results might fall into two categories:

Non-paternity event or misattributed parentage event in your tree
The term ‘non-paternity event’ (NPE) is used in genetic genealogy to refer to any situation where DNA testing shows the biological father is not as expected.  It may be that the man we called ‘Dad’ is not in fact our biological father.  Or perhaps DNA testing of a close family member such as a sibling indicates that they have a different father.  It could even be that neither parent is biologically linked, or perhaps the DNA connections change a generation or so further back.  To allow for situations where the mother is not as expected, the term term ‘misattributed parentage event’ is often used as an alternative to ‘NPE’.

We need to keep this possibility in perspective.  FTDNA, one of the main DNA testing companies, assess the NPE rate at about 1-2% per generation. The International Society of Genetic Genealogy Wiki page on NPEs cites a number of studies, some of which have concluded that historical NPE rates were much higher than more recent times.  In other words, you’re more likely to find an NPE some generations back.  However with the passing of generations,  the cumulative impact of these per-generation statistics is significant.

When faced with evidence of an NPE it’s important not to jump to conclusions.  The above-mentioned ISOGG page sets out a whole range of possible explanations for how this might have come about, including:

  • Illegitimacy outside marriage
  • Infidelity within marriage
  • Remarriage, in which the child takes the surname of the step-father, perhaps after the untimely death of the biological father (e.g. in wartime)
  • Rape
  • Adoption, including hidden or informal adoption
  • Intentional or unintentional baby swap
  • Unintentional embryo swap
  • Sperm donation

It is entirely possible that your DNA test has uncovered a well-kept secret – even, in the case of unintentional baby/ embryo swap, a fact unknown even to the parents.

Another tester’s NPE or parents unknown that impacts on your family or ancestry
More likely is the possibility that your own DNA results will be absolutely in order, but that another tester’s are not.  Although my own DNA test has uncovered no direct NPEs, in my wider tree I’m aware of nineteenth century illegitimacy before marriage; infidelity or possibly rape (a child conceived while the husband was away at war); and informal adoption and remarriage following the death in WW1 of the father, resulting in the registering of the child in the name of the second husband.  An unexpected high match between you and another tester may indicate that their biological father is someone connected with you.  More likely yet, in my experience, is that some of your matches will have tested specifically in the hope of finding their own missing father, grandfather or even (if they are adopted) both biological parents.  You may find that quite a few of the people who match you but have no tree linked to their DNA results will fall into this category.  I will always do whatever I can to help any of my good matches in this situation.

How does the DNA reveal this?
Think back to the Shared centiMorgan Project chart in my last post.
We noted that we can expect to share 3485cM with a parent, but that the parameters are 2376-3720.  If my DNA results reveal a match of that size then there is no doubt: either I am that person’s parent or they are my parent.  Conversely, if my father or a close family member on his side (my aunt, uncle, cousin) has tested but we share no DNA at all, then either this is not my biological father or he is not a full sibling to this family member.  If, on the other hand, a completely unknown person matches me at half sibling or at cousin level, then one of my parents or one of my aunts or uncles had a child about whom I had no knowledge.

It is unlikely to be as straightforward as that. More often, our match will be more distant – the amount of shared cM will be smaller.  What we have to do is work with what we already know, gradually homing in on where we connect.  For example if I don’t match with A’s mother, then even though A has no paternal tree at all we can assume I do match with the father.  If A matches with my maternal cousin as well as with me, then we know it is my maternal side where we match.

In a sense, in this type of situation we turn the search on its head.  As outlined in my last post, the usual way to use DNA test results is to look at the amount of DNA shared (expressed as centiMorgans, the higher the number the closer the match) and then to look in our trees for our Most Recent Common Ancestor – Bingo! End of search!  Clearly, if our match has no tree and no knowledge at all of their birth family we can’t do this.  We can only progress if there are other people who match both of us.  Let’s say A is seeking their birth parents, and A and I match at around second cousin.  B and C also match the two of us but at around third or fourth cousin level.  If I can find in my own tree where B, C and I share an ancestor, there’s a good chance that A and I will have common ancestors one or two generations closer to me on that same line.  However, unlike me, A’s goal is not to identify which set of great grandparents they got that segment of DNA from.  What they want to know is the name of an unknown parent.  Therefore, if we can identify our own Most Recent Common Ancestor, they will now need to work forward from that, to identify their biological parent.  In the above example, on the basis of information available from our shared DNA, I can’t tell them that, but I can say that their unknown parent is probably the grandchild of these two specific people who are my own great grandparents, and that has narrowed down their search quite considerably.  It may take a while but eventually, as more people test we may have more testers matching both of us at a closer level, and we can continue to narrow down the possibilities.

Undoubtedly the above scenarios raise a number of ethical issues. We will consider them in my next post.

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Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones. Click [here] to read all of them in order, or to dip in and out as you wish. You’ll also find lots of resources and useful links

Using DNA testing to develop your family research

Last September I wrote about deep ancestral DNA testing using Y-chromosomal and mitochondrial tests.  I said back then that I would write more about my experience of using DNA testing alongside traditional documentary research to develop my family tree.

Today I’m going to introduce the topic of autosomal DNA, including inheritance patterns and an overview of how we can use autosomal DNA testing in our family research.  The following four posts will look at:

  • unexpected results;
  • ethical issues, particularly flowing from unexpected results;
  • the benefits of asking certain other close family members to test for you;
  • different testing companies.

There’s a lot to say and if this is new to you it will seem complicated – it certainly did for me when I first started.  I found the best way to learn was to read to understand the basics, and then just do it!  So I’ll do my best to introduce it all in small chunks.  And alongside my own discussion of the topic, and my own experiences, I’ll offer links to websites, books and other resources. There are several online groups, including on Facebook, where you can ask questions if you’re stuck, and people are helpful.  After the initial introduction of some key points over the next few posts I’ll move back to other family history topics, interspersing with more DNA posts from time to time.  I do appreciate that this won’t interest everyone, but it’s a growing and important part of genealogical research these days.

Autosomal DNA
The DNA tests we see advertised for genealogists use a different type of DNA from the two types I wrote about in that previous post.  What they test is autosomal DNA (atDNA).  This comprises the twenty-two pairs of non-sex chromosomes within the nucleus of every cell.  There is also an additional pair of chromosomes within the nucleus, which are the sex chromosomes.  Females inherit one X chromosome from their mother and one from their father.  Males inherit just the one X chromosome from their mother and the Y chromosome from their father.  As we have seen, the Y chromosomal DNA requires a completely different test.  However, some atDNA tests do include testing of the X chromosome, and this can give additional information to help us to understand which of our lines to focus on when we have a match, but for now I’m focusing on the non-sex, autosomal chromosomes.

Building on what we covered in my previous DNA post, autosomal DNA differs from mitochondrial and Y-chromosomal DNA in the following ways:

  • Mitochondrial DNA is inherited by all babies from their mother but only her daughters pass it on.  Boys, therefore, receive this DNA but do not pass it on to their children.  Y-chromosomal DNA is passed on from the father only to his sons.  Daughters do not receive it at all.  By comparison, atDNA is passed on to every child.  There are no differences whatsoever based on the child’s sex.
  • Mitochondrial and Y-chromosomal DNA mutate (change) very, very slowly.  They are passed on largely unchanged.  This means that our mitochondrial DNA (and for males, Y DNA) can connect us to specific ancestors and their kin who lived many thousands of years ago, perhaps in the Middle East, perhaps in Africa.  By contrast, the atDNA changes with every successive generation.  I’ll say more about this below, since this is at the heart of how we use it in our genealogy research, but for now, just note it as a contrasting feature with these two other DNA types.
  • The operation of mitochondrial and Y-chromosomal DNA, passing largely unchanged from parent to child, means that when we follow it backwards we follow just one line: your mitochondrial DNA has passed to you from your mother, to her from her mother, to her from her mother, and so on, back through time.  The Y DNA has worked in the same way, from father to male child, right back through time.  Those types of DNA, then, can take us on a journey up a very narrow and specific part of our family tree: your mother, your maternal grandmother, just one of your 8 great grandparents, just one of your 16 great grandparents, just one of your 32 GGG grandparents, and so on.  (And the same for Y DNA for male inheritance.)  By contrast, autosomal testing provides a 360-degree coverage of all your atDNA inherited from all of your lines.  There is no difference for children of different sexes.
  • Experts tell us that at the present time atDNA testing is accurate only for five or so generations.  I have found connections further back than that which fit with the smaller amount of DNA and with my documented family tree, and that’s good enough for my purposes, but the experts say five generations or so.

Autosomal DNA inheritance
I said above that our autosomal DNA comprises twenty-two pairs of chromosomes.  One chromosome from each pair is inherited from our mother, the other from our father.  This means that we get half our autosomal DNA from our mother and half from our father.  Obviously, each of our parents also inherits half of their autosomal DNA from their mother and the other half from their father, and so on, back through time.

This might suggest that the inheritance of atDNA is very tidy, with progressively smaller, exact fractions from each of our ancestors: half from each parent, a quarter from each grandparent, an eighth from each great grandparent and so on.  But that is not the case.  The atDNA we receive from each parent will not be an exact 50-50% split of what they received from each of their parents.  On the other hand it isn’t entirely random either: there are parameters.

When we talk about amounts of atDNA we don’t usually refer to it in percentages.  There is a unit of measurement: the centiMorgan (cM).  One of the authorities on DNA testing for genetic genealogy is Blaine T. Bettinger.  Since around 2015 he has been investigating these parameters for centiMorgan inheritance through a research project known as the Shared CentiMorgan Project. It is the go-to document for calculating likely relationships based on DNA.  As I write this, his published results (Version 4) are up to date as of March 2020.  Click the following chart to see it full screen on Blaine’s own website.

These findings are based on submissions from almost 60,000 people who have tested their own autosomal DNA and have known and documented relationships with other testers who share some of their DNA.  Locate yourself at SELF on the chart, and from there look around the wide range of relationships with whom you might share atDNA.  You’ll see, for example, that the average amount of atDNA you share with a parent is 3483cM, but based on real test results from these 60,000 participants it could be as low as 2376 or as high as 3720cM.  The average you’ll share with a full sibling is 2613cM but it could be as low as 1613 and as high as 3488cM.  The average shared DNA with a great grandparent will be 887cM but it could be as low as 485 or as high as 1486cM.  Looking further afield, the average amount shared with your 4th cousin is 35cM but it could be as low as zero or as high as 139cM.

How can we use this information to develop our family trees?
By now you may be thinking:

  • ‘Why on earth would I want to know how much DNA I share with a 4th cousin?’
  • Or ‘My great grandparents are long dead.  I couldn’t access their DNA even if I wanted to.’
  • Or even ‘Yes, very nice.  And this has what, exactly, to do with developing my family tree?’

When we take a DNA for genealogy test and agree for the results to be included in a pool of testers we will be able to see which of the other testers share DNA with us.  Depending on which testing company you use, you will be told the name (or pseudonym) of your match; the amount of shared DNA in centiMorgans; the likely relationship you have with that person (based on the amount of shared cM); and you may possibly have information regarding the exact shared segments plus access to the other person’s tree.  You will also be able to see other testers who match both yourself and that other person.  The results are never displayed in a way that enables another person to see private information about your DNA, simply that you match with them at specific segments.

If my atDNA and another person’s atDNA is exactly the same at one or more places (segments) throughout the twenty-two chromosomes, then that means we have both inherited that part of our DNA from common ancestors.  The higher the amount of DNA we share (the centiMorgans), the closer our relationship is.  If, based on the shared cM, our suggested relationship is around 4th cousin, then we will be looking for a Most Recent Common Ancestor (MRCA) at around 3xG grandparent level.  We now shift to looking at our trees.  Assuming we have both done accurate research, if we both have the same ancestor named as 3xG grandparent (or thereabouts, e.g. it could be my 3xG grandparent and the other person’s 4xG grandparent) then we have found our match.  Based on this we now have the following:

  • a further piece of evidence that our documentary research is correct;
  • proof that there were no adoptions or unexpected paternity events along the way;
  • a new cousin who shares our interest in family history and DNA.  From here on, if you’re minded to, you might be able to share research and new discoveries (I have become great friends with some of my ‘new’ cousins, while for others the connection has been more focused and businesslike);
  • and something else that I think is rather wonderful: you now know that this little piece of you has come down through several generations, unchanged, from an ancestor whose name you have and whose life you have been researching.

Of course, it doesn’t always go as smoothly as that.  Your match might not have a tree – I have often taken what little information they have and worked their tree back to find our shared ancestor: the MRCA.  Your match might not even know who their parents are: I have now used DNA to help one person find their biological father and another to find a missing grandfather.  On the other hand, it may be that your match’s tree is more advanced than yours, and that this DNA connection will help you break through a brick wall and take your tree back a generation or two further.  But we can’t do any of this without other testers: our distant cousins living now, who have also tested and whose test results combined with our own are the key to unlocking information about our shared ancestral lines.

Find out more
Blaine’s excellent book, The Family Tree Guide to DNA Testing and Genetic Genealogy was my starting point in getting to grips with how this all worked.
You can read more about the Shared cM Project [here]
And download a PDF with (a LOT!) more information [here]
His website is perhaps of more use if you’re already familiar with DNA for genealogy and are looking for more information about specifics.
His YouTube channel is [here]

Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones.  Click [here] to read all of them in order, or to dip in and out as you wish.  You’ll also find lots of resources and useful links

Deep ancestral DNA testing

How far back have you got with your family tree?  150 years…?  300 years…?
How about two hundred thousand years…?!

One of my goals for 2019 was to develop my understanding of DNA for genealogy.  I became interested in this in 2013 but hadn’t made much progress.  Although the main type of DNA testing used for genealogy is autosomal, my introduction was through learning about two other tests: mitochondrial and Y-chromosome.  In future posts I’ll say more about my experience so far of using autosomal testing alongside traditional documentary research.  But today I want to start by going back to the beginning… both in terms of my own DNA journey and indeed almost to the beginnings of the human race.

Please note: I couldn’t even pretend to be an expert in what follows.  There’s a reading list at the end if you want to explore further.

Meeting the Izzards
Back in February 2013 I watched a two-part BBC series called Meet the Izzards.  Actor/ comedian/ campaigner Eddie Izzard took two DNA tests: a mitochondrial test which would follow his mother’s mother’s mother’s etc line all the way back through time; and a Y-chromosomal DNA test which would reveal the same for his paternal line.  At the time of writing, the programmes are available on YouTube:

Episode 1, dealing with his maternal line
Episode 2, dealing with his paternal line

Mitochondrial and Y-chromosome DNA inheritance
We all receive mitochondrial DNA (mtDNA) from our mothers, but only females pass it on to their own children.  Sons receive it, but can’t pass it on.  Y-DNA, on the other hand, passes only from father to sons.  The daughters never receive it.

So my brother and I can each take a mitochondrial test, and they would reveal exactly the same information about our maternal line deep origins.  But only I have passed it on.  His children have received the mitochondrial DNA of their own mother.  On the other hand, only my brother received our father’s Y-DNA.  He has passed that on to his sons but not to his daughter.  My sons have received the Y-DNA of their father (but not, of course, his mtDNA).  If I want to find out about my direct paternal line, I have to ask a male relative either in my direct paternal line or descended directly from that line to do it for me – my brother, nephew, father, grandfather, paternal uncle, a cousin who is the son of a paternal uncle, etc.

As a man, Eddie Izzard was able to take both tests: the mitochondrial and the Y-chromosomal.  It was his journey that inspired me to embark on my own.

Haplogroups and ‘clan mothers’
After watching the TV programmes I read Bryan Sykes’ book: The Seven Daughters of Eve.  Fellow of Wolfson College, and Emeritus Professor of Human Genetics at the University of Oxford, Sykes was a pioneer in the extraction of mitochondrial DNA from ancient human remains.  In this book, aimed at the non-scientific reader, he outlines how he did this, as well as some of the research findings flowing from that:

We all have one common ancestral mother.  She lived 200,000 years ago in Africa, and is referred to in DNA circles as ‘Mitochondrial Eve’.  We are also all descended from a common ancestral father.  He too lived in Africa, and is referred to as Y-chromosome Adam.  (DNA from Y chromosomes is harder to extract and was developed a little later, but there are parallel findings to the following for Y-chromosome testing.)

About 60,000 years ago, some of Mitochondrial Eve’s descendants crossed over the Red Sea, leaving Africa for the first time.  So started the worldwide human diaspora.  Some of our forebears headed north, some east, some west – obviously a gradual migration, taking thousands of years.  It wasn’t until about 40,000 years ago that the first anatomically modern human beings entered what we now call Europe, but they came via different routes.  Thanks to DNA, scientists are now able to trace their progress.

Sykes found that the vast majority of (indigenous) modern Europeans can trace their mitochondrial DNA to one of seven women – these are the ‘Seven Daughters of Eve’ referred to in the title of his book.  Scientifically, the terminology is that modern Europeans fall into one of seven mitochondrial haplogroups: U, X, H, V, T, K and J.  However, since the point of Sykes’s book was to bring the science to a more general audience, he focuses not on the scientific terminology of seven ‘haplogroups’, but on those seven women living way back in the distant past, with whom these seven distinct haplogroups originated.  He even gives them names, each one corresponding to the letter of the haplogroup she heads up: Ursula corresponds to Haplogroup U, Xenia to Haplogroup X, Helena to H, Velda (V), Tara (T), Katrine (K) and Jasmine corresponds to Haplogroup J.  While each of these women was a descendant of our common mother ‘Mitochondrial Eve’, if you are of indigenous European descent, one of these seven women will be your (many times) great grandmother.

Later, with additional data from Scandinavia and Eastern Europe, Sykes added Ulrike as an 8th clan mother/ haplogroup.  But the science continues to develop, and it seems the precise number and arrangement of haplogroups is not yet fixed.  There are also an additional 29 haplogroups worldwide, all with ‘clan mothers’ named by Sykes and each associated with a different geographical area or native people.  You can read more about this here.

The science bit
It is the mitochondrial DNA we receive that identifies each of us as belonging to one of these haplogroups, and this mitochondrial genome usually passes unchanged from one generation to the next.  Periodically, however, it mutates.  (This isn’t a bad thing; it just means it changes.)  It is this mutated (slightly changed) version that will now be passed on by that line, and all descendants of this woman from this point onwards will be distinguishable as a different branch (or ‘subclade’) of the line.  These mutations, or ‘markers’ are what DNA specialists look for when analysing the mitochondrial genome for ancestry purposes.  By comparing these markers with other testers and with the DNA signatures typical of people in particular geographical regions, and then by calculating how far back in time each mutation occurred, it’s possible to suggest the broad migratory routes our ancestors appear to have taken to get from Africa 60,000 years ago to where we are now.  What this means is that rather than simply being of haplogroup U, X, J, etc, we are each identifiable as part of a subclade, such as J1 or J2, and even smaller sub-groupings than that, like J2a1a1a2.  (i.e. everyone in haplogroup J2 is descended from the one same many-times grandmother, but if you share a subclade with another person, like J2a1a1a2, then you also share a much closer common maternal ancestor.)

Combining DNA research with other disciplines
What really fascinates me about all this is how DNA evidence is now used in combination with archaeology, palaeontology, anthropology, linguistics and other disciplines to push back the frontiers of knowledge of our deep ancestry.  Here are some examples:

  • DNA has proven conclusively that although early modern humans and Neanderthals lived separately, about 55,000 years ago they did produce some joint offspring. Consequently, today the average European has just less than 2% Neanderthal DNA, while people whose origins lie in Asia, Australia and the Americas have an average of just over 2% Neanderthal DNA.  It’s possible that this is where we get (amongst other traits) our straight hair and our ability to retain weight (– this was a good thing 55,000 years ago).
  • Mitochondrial DNA has helped to solve a mystery about the apparent annihilation of Celtic as the language of Britain prior to the Anglo-Saxon invasions. The almost complete disappearance of the Celtic language from England, leaving it only in the West of the British Isles, was suggestive of the massacring of the people.  And yet DNA shows this did not happen.  Only the language was lost; the people remained.
  • Comparisons of mtDNA and Y-DNA in the British Isles has also shown that not all Viking invasions were violent. If the reverse were true, there would be a great deal of Viking Y-DNA and very little Viking mitochondrial amongst the British people, but this is not the case.  Therefore many Viking incomers were couples who came peaceably and settled.
  • It was mtDNA sequencing that proved the skeleton found under a car park in Leicester was that of King Richard III. His mitochondrial DNA, as received from their mother, was passed down through the female line from his sister to two relatives alive today.

Can this help with our documented family trees?
The autosomal DNA test – the one usually taken by people researching their family trees – gives us a complete 360-degree picture of the bits of DNA we’ve inherited from each ancestor of the last five generations or so.  Mitochondrial and Y-chromosome testing won’t help with this.  Since both types of DNA pass largely unchanged down the male or female line, our mitochondrial and/or Y-DNA links us back thousands of years to specific individual women and men whose names we will never know.  An mtDNA test, then, will verify that at some point we shared an ancestral mother, but the very slow mutation rate of this type of DNA means that it may be possible only to narrow this person down to a 500-year period.  A Y-chromosome test has a slight advantage in that it passes along exactly the same route as the surname.  Assuming, then, that there have been no adoptions, no elective name changes and no ‘non-paternity events’, a Y-DNA tester can expect to find they match with others of the same surname.  The sharing of the Y-DNA shows that they are definitely related on the paternal line.

Certainly for me, the decision to take a mtDNA test was separate to my interest in my family tree, stemming from a curiosity about my deep ancestral origins.

Further reading
Trust me – these are all aimed at non-scientists! (But I recommend starting with Meet the Izzards on YouTube.)

Bryan Sykes: The Seven Daughters Of Eve
Bryan Sykes: Blood of the Isles – outlining how DNA has contributed to understanding the nature and implications of successive invasions of the British Isles.
Sykes has also written a number of other books about various aspects of DNA.

Karin Bojs: My European Family: The First 54,000 Years – a fascinating, and up to date account of how genealogists, geneticists, anthropologists, linguists and other experts are working together to make sense of the deep history of the human family.  Karin Bojs is science editor of a Swedish newspaper, and in this work uses the general information to make sense of not only her own roots but also those of Sweden and Europeans more generally.

Blaine T. Bettinger: The Family Tree Guide to DNA Testing and Genetic Genealogy – aimed at genealogists who are not scientists, this book covers mitochondrial, Y-chromosomal, autosomal and X-chromosonal DNA, explaining the science and then, importantly, how we can apply the results in our family research. Blaine T. Bettinger also has a blog and a YouTube channel.  He has helped me to make sense of a lot of this DNA stuff, and I’ll definitely be mentioning him again when I write about autosomal DNA for genealogy in the future.

*****

Edited August 2020
My posts about DNA are aimed at complete beginners and aim to provide information in manageable chunks, each post building on previous ones. Click [here] to read all of them in order, or to dip in and out as you wish. You’ll also find lots of resources and useful links