Focus On: Getting Started with Genetic Genealogy

In Spring 2018 I took my first DNA test, and plunged into the deep end of the world of Genetic Genealogy. Although I’m still learning new things all the time, I’ve already learnt so much! I’d really like to share my knowledge to date, collating all the information I’ve gleaned, in one place.

For the sake of this article, I’m going to assume you’ve taken / plan to take your DNA test with Ancestry. It doesn’t really matter if you’re using an alternative company, most of the blog will still be relevant.

1. The Science Bit

dna strand

Firstly, don’t worry if (at first) you don’t understand all the science. It can take a while to wrap your head around some of the more complex details. To get started all you really need to know is that your DNA matches will share some DNA with yourself. It’s measured in centimorgans, abbreviated as cM. The amount of cM you share with an individual is a good indication of their relationship to you. There’s a great tool that can tell you the likely relationship between you and a DNA match, based on the amount of shared cM. But we’ll get to that in a bit…

Firstly, there are loads of great sites explaining the science behind DNA inheritance. For a really thorough explanation, check out Wheaton Surname/Beginners Guide to Genetic Genealogy

2. All Cousins are Different

Within the first week of getting my results I was thrown – I had three distant cousins descended from the same ancestor as myself. All three were in my list of Ancestry matches. However, the cousins did not all match with each other.

This really took me some time to get my head around. How could we all be descended from the same person but not all be on each others list of matches? Yet the answer is glaringly obvious, and so simple. I’d already read the answer in the multiple science / explanation websites that I’d browsed. It just hadn’t clicked, until I experienced it first hand – and read the ‘deck of cards’ explanation…

DNA inheritance is like picking a random card

Imagine DNA as a pack of 52 cards. Everyone has 52 cards, and everyone gets half from Mum and half from Dad. That means out of the 52 cards your Mum holds, she’s given you half but it’s a shuffled pack and each time a new baby is born that pack is re-shuffled. Imagine your Mum shuffled her cards and gave you an Ace of Spades. That Ace of Spades has been passed down from her great-grandmother, Mary. You inherit it, but your brother doesn’t. However, he does inherit the Queen of Clubs, which also just happens to be a card paced down from Mary. Great-grandmother Mary had 3 children, they all had multiple children. Some of these descendent have the Ace of Spades, some have Queen of Clubs, some have other cards from Mary, and some have none.

You will match with those descendants that inherited the Ace of Spades – but your brother won’t (he has the Queen of Clubs). Likewise, your brother matches descendants with the Queen of Clubs but you don’t. Your all related, but you don’t all match each other.

This is why completing DNA tests on multiple members of your family can be helpful.

DNA is like pick and mix

DNA is like a random pick a mix or a box of chocolates – you never know what your going to get!

3. My Matches

Once you receive your DNA results you’ll be able to view a list of matches. These are all people that share some DNA with you. By default Ancestry lists them in order of relationship – so closest matches are at the top of the list.

Link your DNA to your family tree (public or private) and if you are lucky you might have some ‘shared hints’ with these DNA matches. This means that a hint that appears in your ancestry tree is the same as a hint within your DNA matches’ tree. But, bear in mind that these hints still need to be carefully checked. Ancestry might be giving you both the same hint but it doesn’t mean that hint is correct.

I soon realised that reviewing all my matches was a huge undertaking, and that some matches seemed inactive, some had private trees and some had no trees at all. So where to start? I contacted obvious matches, started taking notes [both using Ancestry’s ‘add note’ feature and offline]. I created contact lists, shared matches lists etc but soon became overwhelmed. I needed some help…

4. Chrome Browser Extensions

chrome extensions can be useful

I’ve made use of two free chrome browser add-on’s or extensions. Both can be found by searching here; and a full description, instructions etc can be viewed at their individual websites

AncestryDNA Helper – You can use this tool to download all your Ancestry matches into a spreadsheet, including your notes. Be warned it can take a really long time to process.

MedBetterDNA – This tool makes your notes visible on the DNA Matches page, saving you from having to go into every individual match to read your notes. You can also create searchable filters by adding a # to keywords within your notes. In addition MetDNA allows you to filter out matches by confidence of match, and hide those with no trees or private trees.

5. Shared Matches – Triangulation, Surnames and Locations

It’s not always easy to work out how you are connected to a match, but looking at ‘shared matches’ can help. These are people that share DNA with both yourself and one of your matches. Sometimes a good match might not have a public tree, but one of your shared matches does – and this can provide clues as to how you might be related to the user without that tree information.

DNA triangulation

You’ll still need to contact the user without a tree, but at least you have an opening gambit – “hello, is it possible we are connected via surnames X, X and X” is a lot more engaging than “hello, we’re connected somehow, can you look at my tree or do you have an online one I can view?”

When looking at your shared matches you may start by trying to determine whether you have a shared surname – but don’t forget to check shared locations. I have lots of Williams and Davies in my family tree – as do many of my matches. But my Williams and Davies come from distinct areas. I’m more interested in matches that share ancestors from the same location than the surname itself – especially as some of my ancestors were illegitimate.

6. Chromosome Browser

The subject of shared matches leads me on to Ancestry’s biggest failure – the lack of chromosome browser…

chromosome browser

All those bits of DNA that you share with different relations are easier to see on a Chromosome Browser. What’s that, I hear you Ancestry users cry? Well, it’s a tool that Ancestry don’t have but really really should!

Other sites, (I’ve been using My Heritage and Gedmatch), include information – not just on how much cM you share with a match – but which bits of DNA you share across which segments, and on which chromosomes.

Luckily quite a few sites allow you to download your Ancestry DNA test results for free. Find out more about how to do this here:

The benefit of loading your results onto other sites is that you are increasing the likelihood of reaching even more matches. In addition, on the above mentioned sites, you’ll be able to see a chromosome browser for each of your matches, and this may include some users who have also tested with Ancestry.

Note: please read the terms and conditions, and privacy notices of all websites, and ensure you (or the DNA test taker) is happy, before you upload.

Does all this talk of chromosome browsers sound complicated? It’s actually not, but it’s hard to explain when you can’t see it! Being able to see where within a chromosome you match a distant relative can help with triangulation – if a group of shared matches all match across the same part of a chromosome then there’s a good chance they are all descended from the same person.

7. DNA Painter

DNA Painter

Image of DNA Painter’s chromosome map on homepage, (c) of DNA Painter website and reused with permission of Jonny Perl

My Heritage and Gedmatch, amongst other sites, include a chromosome browser for each of your matches. This can be in the form of a visual image for each of your matches, or a table showing shared data. But wouldn’t it be great to see the shared DNA of several matches all in one place? Even better, if you mapped the shared DNA of known matches couldn’t this then be used to help you work out your connection with unknown DNA matches?

In other words, if I could see the DNA of my grandfather, wouldn’t I then be able to see if someone else’s DNA also matched his?

This can all be achieved using DNA Painter. This site allows you to create a free profile, allowing you to load your shared DNA data to create a visual image of your DNA map. It sounds complicated but it’s really easy. Just give it a try yourself!

my DNA profile so far

My DNA profile. Image produced using DNA Painter. Please request permission from Natalie Pithers to re-use image.

DNA Painter also supplies another essential tool, Shared cM v4. Simply type in the amount of cM you share with a match and it’ll provide you with information on your likely relationship – e.g. it’s 55% chance you are 4th cousins. Again, very easy to use.

DNA Painter have also recently launched a tool called What Are the Odds? (WAO) that can be used to test hypothesis regarding how you might be related to a match. I’ve not used it in earnest yet but I’ve heard others report that it’s now part of their essential Genetic Genealogy toolkit.

8. Use a System

There are lots of different systems or methods for recording and tracking your DNA matches. I strongly suggest joining the Facebook group – Genetic Genealogy Tips and Techniques, created and managed by DNA guru Blaine T. Bettinger. This group is full of fantastic suggestions and methodologies. For example, using shared matches and colour coding to work out relations – called The Leeds Method. It’s also worth keeping an eye on Bettinger’s blog, The Genetic Genealogist and for beginners help try, DNA Discoveries

9. Paper Research

It’s really easy to get excited over a DNA match that seems to share a surname with you, or maybe a distinct location. But, sharing a piece of DNA, does not negate the need to use traditional genealogy methods. The two go hand in hand. Think of DNA as a clue – or a secondary source – in most cases it needs further evidence to back it up. It’s easy to look at a DNA matches tree and assume that it’s correct, because it links back to a shared ancestor via a sibling that you also have in your tree. However, make sure you double check everything. Is this person really descended from that branch? If they’ve made a mistake you might be linked in a differet way, or even on an entirely differnet line! Don’t forget, you might even be related via several different branches of your tree.

There is a lot of debate in the genealogy community about the usefulness of matches with whom you share a tiny amount of DNA. Some sites or forums suggest ignoring any matches below a certain amount of cM – perhaps even below 20 cM. For those with loads of good, 2nd and 3rd cousin matches, that may well work. However, for many people, particularly those of us outside of America, we may have very few (or possibly even zero) matches above 4th cousin level. Does this mean we can’t use genetic genealogy? Of course not….but it does mean that we need to use the paper resources (see point above) and be aware that some tiny DNA matches (e.g. below 7 or 5 cM) may be entirely coincidental. You may find this referred to as ‘false positives’.

10. Think Outside the Box

genetic genealogy means thinking outside the box

Working out how you are connected to a shared match can be very challenging. Be prepared to use all your logic skills! You might find a match with a very small tree…put perhaps you can find someone within that tree in a larger public tree? Perhaps someone has no tree, but they have an unusual user name – can they be found online, do they have a tree on another site? You’ve found a match with a shared surname, but still can’t see the connection? Build a Quick and Dirty (QAD) tree, branching out along all the collatoral lines to try to find the connection. Just don’t forget once you find a potential connection you need to go back and turn that QAD into a well evidenced and fully sourced masterpiece before you combine it with your carefully researched master-tree!!