Today I have pretty things for you! For ages I wanted to create a colourful fan tree. I had no idea how to go about doing that but suspected it would involve a lot of work, so I was particularly impressed when, a while back, Jonny Pearl introduced the facility to do this very quickly and easily on his DNA Painter site.
I wrote about DNA Painter earlier this year as part of my mini-series on using chromosome browsers as part of DNA research for genealogy. As explained in that previous post, DNA Painter is brilliant for mapping out your DNA segments, but in theory even if you don’t intend at this stage to use the main DNA functions, you could still get your own colourful fan just by uploading your tree to the site. You do this by downloading the GEDCOM file from your online tree or your own software or simply by inputting the information manually.
Once loaded, your tree will appear as a pedigree with each of the lines colour coded. The DNA Painter default palette uses pretty much the same colours I use on Ancestry to assign known DNA matches to each of my great grandparents’ lines, but here on DNA Painter the default paternal grandmother and maternal grandfather colours were the wrong way round for me. It was very easy to flip the colours. Editing and building the tree is very straightforward too. You can hover over any ancestor to edit their information, add their parents or delete them, and you can mark them as a genetic ancestor – someone who is a common ancestor confirmed not only by paper trail but also by DNA. Fly your cursor over any ancestor and then select View/Edit → Edit or Add Notes to change any information about them, including the colours used for them and their ancestors.
From this point you can go to the three options at the top left hand corner of the screen: TREE / FAN / TEXT. Tree is the default – the pedigree. Text is a handy pedigree list of all your ancestors, with dates and places of birth and death. However for me the fan is the most exciting part. It only goes to 10 generations and I have some lines further back than that, so they are not included. Already, though, you can see at a glance how well you’re doing and where you have gaps.
I’m sure the arrangement in the fan above is obvious, but in case it isn’t: from left to right, the colour blocks are pale blue for my paternal side and pink for maternal. Then I have blue for my paternal grandfather (with violet and blue for his ancestors); yellow for paternal grandmother (with orange and yellow for previous ancestors); green for maternal grandfather (with turquoise and green for his ancestors); and finally salmon pink for maternal grandmother, with deeper pink and browny pink for her ancestral lines.
For all versions of the fan tree shown in the images in this post, you can hover over any individual person’s ‘box’ to see their name, vital dates and their relationship to you. At the same time on the left of your screen you’ll see the lineage from that person to you. I couldn’t show this in these images because the screen shot process disables the hovering cursor.
You can also click on ‘Tree Completeness’ over at top right of the screen to get numbers and statistics of ancestors identified at each generational level. All the images in this post click for a bigger version, but you’ll definitely need to do that to see the info on this next image.
DNA Painter Ancestral Trees toolbar
Moving along the toolbar options to ‘Dimensions’, these next two fan charts draw upon all the information you provided when you uploaded or built your tree. First, you can see all your ancestors colour-coded by the age at which they died.
DNA Painter fan tree showing ancestors’ ages at death
Next, ancestors colour-coded by the century in which they were born.
DNA Painter fan tree showing century of ancestors’ births
So far all the charts shown relate simply to the detail of your family tree. However, if you also work with DNA, you can make use of all the following fan charts:
On the upper toolbar, select DNA Filters. The first option is Show Genetic Ancestors. Provided you have already marked which of your ancestors are proven as genetically linked (see above) you will now see how you’re doing in terms of corroborating your documented tree through DNA matching. This is mine.
DNA Painter fan tree showing ancestors with genetic link proven by DNA
My first ever DNA post was about deep ancestral DNA testing: mitochondrial DNA and Y-chromosome DNA. To recap very quickly, everyone inherits mitochondrial DNA from their mother – but only daughters pass it on. This means everyone can be sure that they share the same mitochondrial haplogroup as their mother, their mother’s mother, and so on right back through time. That is illustrated by the following chart. (In fact I have only been able to trace this line back to 3xG grandmother, but even though I don’t know her name, I do know that my 4xG grandmother has the same mitochondrial as me.)
DNA Painter fan tree showing mitochondrial DNA inheritance
Y-chromosome DNA works exactly the same way, but only males inherit it, and obviously therefore only fathers pass it on. So the Y-DNA inheritance path is an exact mirror image of the mitochondrial, following father’s father’s father’s father’s line right the way back. (The chart below showing this is for a man whose DNA I manage. Obviously I can’t get this information from my own DNA.)
DNA Painter fan tree showing Y-chromosome DNA inheritance
The second option in DNA Filters is Show X-DNA Path. At some point I’ll do a blogpost about X DNA. I haven’t done it so far because I don’t have many X matches to use as illustrations. If you already understand X-DNA inheritance patterns the meaning of the following two screenshots will already be clear, and when I do eventually write about this I’ll include them, since they illustrate perfectly the different inheritance patterns for females (the one immediately below)…
DNA Painter fan tree showing X-DNA inheritance for females
… and males:
DNA Painter fan tree showing X-DNA inheritance for males
Because of the dark colour used, it isn’t clear from these last two screen grabs that if you hover your cursor over the dark patch the intensity of colour reduces and you can see the individual ancestors’ names.
I don’t know about you, but I think all of this is pretty cool!
This is the first part in the third and final ‘mini-series’ in my beginners’ guide to genetic genealogy. You’ll find links to all the previous posts [here].
In this mini-series we’re moving on to something called ‘chromosome mapping’ and as an essential part of that we’ll be looking at my favourite tool: the chromosome browser. We’ll focus on:
a definition of chromosome mapping
what a chromosome browser is
what it tells you about your match with another person
how we can use it to identify multiple matches who are descended from the same common ancestors
amount of shared DNA and length of segments as a guide to the closeness or remoteness of a match
‘triangulation’
a case study illustrating how this can all work together
What do we mean by chromosome mapping? When you have a number of confirmed DNA matches and you’ve identified Most Recent Common Ancestors (MRCA) for each of them, you have already started to allocate matches to different branches of your tree. A second cousin, for example, becomes a ‘benchmark’ for more distant DNA matches along the same great grandparent line. We can do this far more accurately if we can actually see the specific segments we share with that second cousin. All these segments, we know, came to us (and to this second cousin) from that known set of great grandparents. If we now find a more distant match (say, a 4th cousin) on one or more of the same segments we can trace those specific segments back even further. Not only will this help to verify our documentary research going back to the next MRCA – likely to be around 3xG grandparents – but also we now know *which* of those previously identified great grandparents this specific segment of our DNA actually came from. I find that very exciting. However, before we can do any of this we need to be able to ‘see’ those segments, and for that we need a chromosome browser.
What is a chromosome browser? Essentially, a chromosome browser is a visual representation of the parts of your DNA that you share with one or more other people. It looks like a series of ‘stripes’ – one stripe for each of your twenty-two autosomal chromosomes. If you tested with FTDNA or 23andMe there will be an additional stripe for the X chromosome.
The following is an example of one of my matches from MyHeritage. I have removed name and contact details, but we’ll call this person A.
The essential information provided here about my match with A on the general listing of all my matches is:
we share 155.4cM across eight segments
this equates to 2.2% of our autosomal DNA
the longest segment is 45.5cM
our estimated connection is ‘1st cousin twice removed – 2nd cousin once removed’
If I click on the pink ‘Review DNA Match’ button, I also see
a list of all the other people on the MyHeritage site who also match A and me
if A has a tree on MyHeritage I can look at that
lists of any surnames we have in common
a comparison of our ethnicities estimates
a chromosome browser representing our match
That’s a lot of information.
At its most basic level, the chromosome browser provides a graphical view of some of that information. It doesn’t provide any surname or ethnicity data, but it does show exactly where, on your chromosomes, those shared segments are.
Below is that match with A as viewed in the chromosome browser. The 22 grey lines represent me: my 22 autosomal chromosomes. The segments where A and I match are those pink lines (segments) on chromosomes 1, 7, 11, 13, 17, 19 and 21. Although you can’t see it on this screen grab image, if I hover my cursor over any of the pink segments while I’m on the MyHeritage website I can see exact locational information (start and end points). I can also download all that information.
These segments are where A and I have inherited exactly the same DNA from the same ancestors.
Using the chromosome browser ‘One to Many’ function A and I now have a lot of information about our match but although we know we’re fairly closely related we still can’t say which of our ancestors we both share. For that we need to look at our documented trees. However, in this case, by a process of elimination of A’s close family members who have tested but don’t match me we have been able to conclude that we are connected on the one part of A’s tree about which nothing is known: a missing grandparent. The chromosome browser may be able to help.
Using the ‘One to Many’ tool, we can use the chromosome browser to compare overlaps between our own DNA and that of several other people – up to seven matches all in one go at MyHeritage. In the example below I’m looking at just two of my matches, comparing exactly where each of them matches me, and looking for any segments where all three of us match. Again, the grey lines represent my 22 autosomal chromosomes. The red segments show my match with A (you can see they are in exactly the same positions as in the above chart, although now they are coloured red). The mustard segments are another person with whom we both match at a close level. We’ll call that person B.
The chromosome browser here shows that I share more DNA with B (mustard) than I do with A (red), and the segments tend to be longer. It also shows that I share lots of DNA with each of them that I don’t share with the other. However, there is one more very important piece of information: A, B and I all share exactly the same DNA in two positions: on chromosomes 7 and 13. Taken as a whole this tells us:
All three of us are descended from the same fairly recent common ancestors.
Between the three of us, we have inherited different parts of the DNA of these common ancestors. What we inherited has come down the line from them to us via our own parents and grandparents – and just to recap a key point from my post earlier this year (Asking other family members to test) siblings (in this instance our respective grandparents) inherit a lot of the same DNA but not exactly the same – which explains why A, B and I don’t all have exactly the same autosomal DNA from those ancestors
I am more closely related to B than I am to A
Since I have previously placed B as my second cousin I already know which set of great grandparents are our Most Recent Common Ancestors (MRCA). Those two 3-way shared segments are proof that A is also descended from these same common ancestors. As a result A now has a name for that missing grandparent
Also as a result, I now know that all those segments coloured red and mustard on my maternal line have come to me from that particular set of great grandparents
Triangulation What we have just seen at chromsomes 7 and 13 is an example of triangulation. To fully understand what this means, we need to understand a key point about chromosome browsers. The chromosome browser represents each chromosome as a single grey line, but that one grey line belies that fact that we get two copies of each chromosome: one from our mother and one from our father. The chromosome browser cannot tell these maternal and paternal lines apart. Therefore when you look at a match on a chromosome browser the segments on those grey lines could be maternal or paternal. They could even (more unusually) be a mix of both if your match is related to you via your maternal and your paternal lines. We have to find some way of working out which.
If you’re working on MyHeritage the Triangulation tool helps with this. It tells you if two or more people match with you at a given segment on the same copy of the same chromosome. In other words – either on your maternal side or on your paternal side. It still doesn’t tell you which side that is, but if you can work it out for at least one of the matches using your documented tree, then you know that this is also where the other ‘triangulated’ person matches you.
You can see how the triangulation tool works in the example above: there is a little box around the overlapping segments at chromosomes 7 and 13. This is MyHeritage’s way of saying that these two segments of DNA shared by A, B and me are indeed on the same copy, and we are therefore descended from the same line. A, B and I triangulate.
Segment length and amount of shared DNA as a guide to remoteness of the match Obviously, these great grandparents from whom A, B and I inherited all these DNA segments, they too inherited their DNA from their own parents, and those parents from their parents, and back through time. Since we all inherit 50% of our autosomal DNA from our mother and the other 50% from our father, when my mother was born she recombined all of this DNA from the line we share with A and B with a whole new set of DNA from her other parent, and then I did the same. This means that DNA shared with closer matches (and inherited from closer ancestors) tends to have longer segments: there have been fewer recombinations. By contrast, shared segments with more distant matches have undergone more recombinations – the DNA is mixed up with that of far more other ancestors – and so segments tend to be shorter. Hence, alongside the total amount of shared DNA, we can also use segment length as a guide to closeness or remoteness of a match.
Once we have identified the MRCA (or MRCA couple) from whom we inherited a decent amount of autosomal DNA (as I did above with A and B) we can use that information to try to place other people who match us more remotely on any of the same segments.
Consequently, attributing a segment to one ancestral couple is not the end of the story because they got it from someone else – or rather one of them did. Therefore when we use new, more distant, DNA cousin matches to take that segment (or part of it) back further, we can work out which of the closer ancestral couple it came from, and which of their ancestors they (and we!) got it from.
A more remote example – a work in progress! The final image, below, shows another One-to-Many chromosome browser example. This time the red lines are B (who was mustard in the last example) and the new person (mustard segments) is C. You can see here that I share far fewer segments with C, and that the segments are shorter. We actually share 31.9cM, and the longest segment is 17.4cM. Using all the information outlined above, we can say that my match with C is more remote than my match with B. Our estimated relationship is given as ‘3rd to 5th cousin’, suggesting MRCAs at 2xG grandparent to 4xG grandparent. Importantly though, MyHeritage’s triangulation tool (the box on chromosome 11) tells me that this match with C is further back along that same line that I share with B. If I can find where C and I connect I will know exactly which more distant ancestors these mustard-coloured segments of my DNA come from. But of course, beyond that set of great grandparents that I share with B there are four GG grandparents, eight 3xG grandparents, sixteen 4xG grandparents, and so on. Our MRCA could be any one of them.
So this one is still a work in progress. By making contact with C, I was able to use the same triangulation process (with one of his closer cousins) to determine which of C’s great grandparent lines we match on. So we know which of *his* great grandparents and also which of *my* great grandparents, but so far analysis and further building of his tree has drawn a blank.
I have reason to suspect that these short segments have come to me from an Irish 3xG grandmother along this line, precise origins unknown, but this is not my common ancestor with C. If I can find an Irish connection along the relevant part of C’s tree, or indeed if I can find a definite Irish lineage for one or more additional people who triangulate with B, C and me along this line, then I may even be able to place this Irish 3xG grandmother’s origins in a specific part of Ireland. I have some ideas for how to progress this, and if they work I’ll write about them in a future post.
In my next post I’ll be continuing this theme by looking at DNA Painter, a third-party tool that helps with the organisation of segment information.
*****
My DNA posts are intended as a beginners’ guide, building up the information in order, in bite-sized chunks. Click [here] to see them all in the order of publication.
Today’s post is the last in my three-part mini-series on practical ways to make the most of your DNA results. The first post, concentrating on what you can do right away, aimed to encourage you to get to know the layout of your testing company’s site and what resources there are attached to your DNA results. The second looked at ThruLines (Ancestry) and Theory of Family Relativity (MyHeritage). Throughout, the importance of constant reference to your family trees is emphasised. DNA works alongside the genealogy; it doesn’t replace it.
Those first two posts focused on using the information being offered to you on a plate and trying to relate it to your own research. In this third post it’s time to get more proactive. Perhaps there’s a gap in your tree or a brick wall, and you want to see if you can use DNA to solve it. Or perhaps there’s a mystery match of a decent size and you want to find where this person connects with you on your tree. In other words, you’re now coming to the DNA with a question.
Before going any further I’m going to tell you about the limitations of my own DNA testing capability. I have no surviving parents, grandparents, aunts, uncles or cousins, and only one brother. Already this means I’m depending on second cousins testing. Now as it happens I do have an unusually large number of second cousins. One great aunt alone was the matriarch of eleven children and about 48 grandchildren. But although I’ve had contact with some, I’ve never met any of them and certainly couldn’t approach any to ask if they would oblige by spitting into a tube for DNA testing purposes to serve my whim. You’d think that out of so many second cousins some of them might have taken a DNA test anyway. Well yes, I know of three. I make good use of the results of two of them, but the other’s results are private.
Whenever I read books or blogposts from respected DNA authorities I’m in awe of the number of family members for whom they have DNA results. It’s plain that some buy DNA tests in bulk when they’re on offer and simply dole them out to family members, all of whom willingly oblige. Add into this mix the fact that DNA testing is far more popular in the US than it is in Europe, and you might start to get an idea of the gap between the kind of results these DNA gurus work with and the paltry results available to me. Apart from my brother and the two second cousins, my closest matches are at 3rd cousin once removed distance and then we’re down to 4th cousins and a lot of matches in the 30-40cM range.
What all of the above means is that I have to work a lot harder to get answers from my DNA. It also means that with perseverence, it is possible. This genuinely is a case where if I can do it, so can you. In fact chances are your matchlist will be stronger than mine.
So with all that in mind, here are some proactive ways you can engage with the information available on your match list and in the attached trees, and use this to confirm your research and/or break down brick walls.
Filtering
You can use the filter bar at the top of your match list to home in on focused information.
At Ancestry you can home in on unviewed matches; matches with common ancestors; matches with public / private / linked / unlinked trees; people you have already messaged, added to a group or made notes for; you can filter by relationship or shared cM; by date of test; and you can search for matches by name or with specific surnames or specific birthplaces in their trees:
MyHeritage allows you to filter by tree details (Theory of Family Relativity; Smart Matches; shared surname or birthplace; has a tree); by proximity of relationship; by country and ethnicity. You can also sort by segment information, full name, and in recent order of testing. And you can search by name or ancestral surname:
I’ve had some success using surname filters to find a common ancestral line, and also using birthplace filters to try to home in on a likely geographical area within Northern Ireland for an ancestral line with records suggesting two conflicting places of origin
Building trees
If you have a decent match that you don’t recognise and they have the beginnings of a tree attached to their results, you can try working their tree back yourself. What you consider a ‘decent’ match will very much depend on how many close or extended family members you have on your matchlist. You may, for example, consider that anything less than 80cM isn’t worth your time. I will do it for much lower matches.
By way of example of what is possible. I’ve done this, and found my connection with:
A 73cM match with only seven surnames (no first names) on the tree. Our connection is 3C1R
A 55cM match with only the name of my match and the name of the person managing the DNA test, who was her son to, work with. Our connection is 4C1R.
A 53cM match with six entries on a tree – two of them private, one ‘unknown’, one with only a first name (which was not entirely correct), and two who were known by names other than the ones given at birth (!) Our connection is 4C.
Remember that if you have close matches and both your trees are well-developed but you can’t find your common ancestors, then either your tree or your match’s tree is wrong, doesn’t go back far enough or sufficiently wide (siblings, half siblings, etc) OR you have uncovered a misattributed parentage in one of your trees. See my previous post about unexpected test results. I have also started to look wider in my own tree building, bringing more lines forward in the hope of ‘meeting’ ancestors of distant cousins who haven’t yet been able to find their way further back.
Clustering
‘Clustering’ is the term used for grouping your DNA matches into groups using the ‘Shared Matches’ tool. The idea is that the resulting ‘clusters’ will represent the distinct lines of your own family tree. Clustering was developed in 2018 by Dana Leeds. Her technique, which became known as ‘The Leeds Method‘ uses a spreadsheet and you can read all about it on her website.
In 2019 MyHeritage introduced an Autocluster tool, based on the same principles, but saving a lot of time by generating the clusters for you at the click of a button.
The idea is that, by pointing to a common ancestral line, clustering narrows down where you have to look for your connection to these matches. You can then focus on each of these family ‘clusters’ as a whole – look for connections in trees, perhaps even build one ‘Quick and Dirty’ tree for each cluster rather than a separate one for each mystery match you want to explore.
A problem I have with all of these clustering techniques is that I don’t have enough close matches to be able to set the systems up. Dana Leeds bases her method on first cousin matches. Larry Jones’s system on Ancestry is based on second cousin matches. I don’t even really get going until 3rd and 4th cousin matches. Nevertheless, I do run the Autoclusters report on MyHeritage from time to time, and I do make use of the colour groupings on Ancestry. I have eight colours: one for each great grandparent, and I add matches to these groups either when I have a confirmed match or when, based on shared matches, a connection looks likely.
Asking family members to test
Back in July I wrote about how our family members’ test results can help us in our research. In that post I wrote about the different ways our various family members’ DNA can help us to isolate the branches of our tree. If you’re lucky enough to have relatives who will take a test for you, that post will help you work out who to ask.
Chromosome mapping
If you tested with 23andMe or if you tested / uploaded your DNA results to MyHeritage, FTDNA or GEDmatch, you’ll be able to view your matches in a chromosome browser. This takes us into a whole new range of possibilities for working with our DNA, and I have another little mini-series of posts about this planned for the spring of 2021.
*****
My aim for this mini-series of posts about practical application of your DNA results has been to provide sufficient basic information to enable you to start to work with your DNA and then to be able to ask informed, focused questions as you need to. And trust me – you WILL need to! I hope you’ve found it helpful.
*****
Note
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, useful links and book recommendations.
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.
*****
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.
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. 🙂
How do they differ?
I’ve put together this table showing features of each testing company that are considered important 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.
*****
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.
*****
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
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!
*****
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.
*****
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.
*****
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
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
English Ancestors 