First look at AncestryDNA

Special message for participants at the 7 October 2023 session-
  • You can read about the recently announce changes to AncestryDNA's subscriptions in Roberta Estes' post HERE.
  • I made reference to this article about Jane Feeney, my two times great grandmother, and the more advanced techniques that were used as evidence to support the relationship - https://tintean.org.au/2020/06/10/jane-feeney-and-dna/. These techniques are not available at AncestryDNA and are on the right hand side of the "Rough Guide to DNA Research" below.
Below at are notes for those who attended the Society of Australian Genealogists' webinar First Look at AncestryDNA.  Others are welcome to use these notes for their personal research.  Please contact me at chrisw9953[at]gmail[dot]com for other uses.  I'll strive to update the notes as there are further developments or my understanding of the area grows.

"Setting the scene"

  • You can read about the "4 types of DNA" HERE.
  • AncestryDNA is an autosomal DNA test (atDNA) and is often referred to as a "cousinship test".
  • You can read about the atDNA inheritance path HERE.
  • You can read about the possibility of sharing atDNA with a "cousin" who has also tested at AncestryDNA HERE. You'll have a match with second cousins or closer relations in all cases at AncestryDNA but only 98% of times for third cousins. The more distant the relationship, the less likely you are to share atDNA with your cousins.

DNA terminology

A segment is a continuous piece of DNA that's measured in centiMorgans (cM). Segments are-
  • inherited from your ancestors and 
  • shared with your DNA matches.
Sometimes people share small segments of DNA that can't be traced back to a common ancestor. We're looking for shared segments that are passed down from common ancestors.

A centiMorgan (cM) is the measurement of genetic distance created by scientists and used by all the major genetic genealogy testing companies.  

As a rule of thumb, the more centiMorgans you share, the closer you're related.

Your aim is to find the relationship with your DNA matches to help you solve your DNA dilemmas. Your relationship is defined by your most recent common ancestor/s (MRCA). If the generations between your common ancestor/s differs between you and your cousin, the cousin relationship is removed by the difference in generations. You can read more HERE as well as find the ISOGG Cousinship Chart.

You can read more about full and half relationships HERE.

We'll often refer to MPE (misattributed parentage events), NPE (non paternal events) and misattributed parentage when a DNA test reveals unexpected results for the tester or one of their ancestors. Studies have shown that these events are far more common that we expect with one in four respondents reporting a MPE between themselves and one of their great-grandparents. That's a 25% likelihood between the tester and their fourteen closest ancestors.

When we are working with a group of three or more unknown matches to help us solve a DNA dilemma, we use our traditional family history research to find the MRCA for the group. We refer to this concept as tree triangulation.

Many of us have two family trees - our genetic or biological family tree and our social or known family tree. While we may do our traditional research on both our genetic and our social family, our genetic family is the one we MUST use for our DNA research.

Recombination is an important but difficult concept when beginning your generic genealogy journey. Louise Coakley is an Australian based genetic genealogist with my "goto" website HERE. I also recommend that you sign up for her eNewsletter HERE. Her description of recombination follows-

"Each parent can only pass down half of their autosomal DNA to each child, so each child will get a random mix of segments from their parents, and consequently a random mix from each grandparent. The diagram below demonstrates how the DNA can be recombined at each successive generation. Three children of the same parents can get quite different mixes of DNA from their grandparents, which means they will match relatives and cousins slightly differently."

Because of recombination, we recommend thinking carefully about who you test and testing near and far as you never know who has inherited that segment of atDNA that's shared with an unknown DNA match that will bring that brick walls tumbling down. 

I share only 7cM with my third cousin Vicki at AncestryDNA. If Vicki tested now, she wouldn't even show as a match as AncestryDNA only reports matches over 7cM now. Sue and Les are our other third cousins. I shared 100cM with Sue and Vicki shares 21cM. I share 30cM with Les and Vicki shares 147cM. It's all about recombination and who received which segments of atDNA from our MRCA, John Killion and Jane Feeney.

Recommended testing path for Australians

AncestryDNA has become the leading testing company in Australian since it entered the market in 2015. Internationally, there are over twenty two million tests in their database. Testing at AncestryDNA is a good investment because you can transfer your "raw DNA" from AncestryDNA to GEDmatch and the other major testing sites with the exception of 23andMe. You can't transfer your "raw DNA" to AncestryDNA or 23andMe. You can read all about transfers HERE.

HERE are my current thoughts on the testing strategy for Australians.

DNA is essential evidence for all family historians to "prove their pedigree"

  • DNA supported by documentary evidence is generally considered to prove relationships from your parents to your second great-grandparents or to the third cousin level. This can be done with your matches at AncestryDNA. 
  • More evidence is required beyond second great-grandparents. This requires more complex techniques which can't be done with matches at AncestryDNA alone.
What's your DNA dilemma? Think about the research goal that you're hoping DNA could help you solve. This will help you identify people who could take a DNA test that could provide useful evidence. 

Here are two useful resources from Danielle Lautrec that will assist you:-
As in all family history, we need to think of the ethical and privacy considerations when-
  • contacting DNA matches, 
  • recording DNA findings and 
  • asking others to take a DNA test.
HERE are the Society of Australian Genealogists' published statements on copyright, privacy and ethics.


The more genetic genealogy I do, the more I see we get 80% of our DNA evidence with 20% of the effort when we understand how to get the most out of our AncestryDNA results and, to a lesser extent, MyHeritageDNA. Generally, this works well back to your second to third great-grandparents back to the early to mid 1800s.

My recommendation is that you move to the right hand side when you have a very good understanding of the techniques required to work with AncestryDNA and have fully explored all you can get from testing there. This session is the beginning of that journey which is covered more fully in the SAG's Analysing your AncestryDNA matches program. You can register your interest for upcoming programs HERE or contact admin@sag.org.au.

Working with AncestryDNA

In the next section, you'll see ten activities that are designed to familiarise you with AncestryDNA's layout and navigation. Stepping through these will demonstrate some of the basics that you need to work effectively with AncestryDNA. 

AncestryDNA offers multiple links into the wonderful help pages which can also be accessed HERE.

In addition, you can access a useful downloadable guide from DNA Adoption HERE. Please note that this excellent resource was last updated in July 2021.

DNA doesn't lie can be misinterpreted!

We need to spend the time and invest the effort into understanding how to work with DNA. HERE is the link to a thirty minute presentation I've recorded to accompany this session. Your DNA - Another vital record shows how I've used atDNA to answer many questions in my Cahill ancestral line.

Activities to help you work effectively with AncestryDNA

  1. Check your public profile taking particular note of trees that can be viewed - click HERE for instructions.  I have many trees but only one is searchable and viewable by the public.
  2. Is your AncestryDNA test linked correctly to a public or private searchable tree?  Click HERE for instructions.
  3. Have you identified Parent 1 and Parent 2 to split your matches into the paternal and maternal sides? Click HERE for instructions.
  4. Why would you want to share your AncestryDNA results? Click HERE for instructions on sharing your results.  Click HERE for instructions on accessing another AncestryDNA test on your account.
  5. Why would you want to download your DNA Data?  Click HERE for instructions.
  6. In the pedigree view of your tree, make sure that your biological ancestors are shown and that the 3 icons are ON for DNA Tree viewing options - as shown in the first image.
  7. From your traditional research, what do you expect your ethnicity estimates will be? How does this compare to your ethnicity estimates at AncestryDNA? Now review your ethnicity inheritance. 
  8. Can you connect a DNA match to your tree? Click HERE for a useful video where this is covered in the first 8 minutes.
  9. Can you add a relationship to your top three known DNA matches? Click HERE for instructions. HERE's some other useful tips.
  10. (a) Use the filters to get a list all your unviewed matches with common ancestors. (b) Sort your match list by date and then filter by close matches.  How many close matches have you had in the last 7 days?  
  11. Click HERE to read about grouping and filtering your AncestryDNA matches. Click HERE to watch a thirty minute video I've recorded on the Leeds Method and my "twisted" Leeds Method.
  12. Attach a "DNA Match" tag to your closest DNA match (other than your child or grandchild) and a "Common DNA Ancestor" tag to your MRCA (most recent common ancestors).  Do you need to use "DNA Connection" tags to connect the match and MRCA?  Click HERE to read about "MyTreeTags".
  13. Click HERE to learn about ThruLines.  Filter ThruLines for "Potential Ancestors".  Review the top two to see if there's any useful information. But remember to "evaluate, evaluate, evaluate" as these are hints to help in your research.

Tips and techniques for working with AncestryDNA

"Know your tree and know your matches"

1. Who should I test to solve my DNA dilemma?

Be strategic in testing and analysis. Ask for access as a collaborator or manager.
  • Always test the earlier generation.
  • Test/analyse Mum and Dad's results before the children.
  • If you can only test/analyse one parent, test all the children and use to analyse the untested parental line.
  • Can't test a parent, what about their siblings or their children?
  • Consider testing full and half cousins near and far.

2. How should I work through my DNA match list?

  • Start at your largest DNA match or your largest DNA match in a group and work out how they are related.
  • Remember that DNA doesn't lie but historical records can record information that isn't genetically accurate.
  • "Prove your pedigree" commencing with your parents and working back by generations.

3. What should I ask a DNA match without a tree who might be able to help me solve my DNA dilemma?

  • See if you can use shared matches to see your common ancestral line.
  • Message matches suggesting the line you might have in common and ask if they-
    • have a public tree or
    • will share details of the birth and marriage dates and locations of their grandparents.
  • Be aware that you get a low response rate to messages at AncestryDNA but the sooner you message after the match appears, the more likely you are to get a response.
  • Think of using social media and other public information to research matches.

4.  Link your AncestryDNA test to a public or private searchable tree

  • Even if it's only a pedigree tree.
  • It must be your genetic and not social pedigree.
  • You can include researched "floating branches" in your tree.
You can read about "hanging branches" HERE.

5. Sharing AncestryDNA tests

  • Looking at relationships through another lens and/or
  • Finding new matches
If someone tests at AncestryDNA and doesn't have an Ancestry account, you can offer to be manager or collaborator of their AncestryDNA test.  

You can read more about sharing AncestryDNA tests HERE.

6. Using AncestryDNA custom groups to cluster your matches 

"Builds on your known DNA matches to the possible relationship with unknown matches"
  • Decide on your groups but always be systematic in grouping
  • Remember groups can always be altered or deleted
  • Alphabetic grouping by family name rarely works

You can read my approach to "grouping" HERE and HERE. Click HERE to watch a 30 minute video I've recorded on the Leeds Method and my "twisted" Leeds Method. You can watch a short video on the Chrome extension, "Click all checkboxes", HERE. Here's the link to the Chrome extension-

7. Add a "hanging branch" for a DNA match to your tree

The goal is to find the MRCA with the match over time. You can read about "hanging branches" HERE.

8. Build "quick and dirty"(Q&D) private, unsearchable research trees at Ancestry

The goal is to accumulate evidence to solve a DNA dilemma (over time). This is a good approach when working with adoptees and assisting other researchers. You can read about building Q&D research trees HERE.

9. Shared matches at AncestryDNA doesn't necessarily mean shared ancestor

You can read about shared matches HERE.

10. Check DNA Discoveries are linked to your profile on the tree connected to your AncestryDNA test

See Activity 5 above.

11. Connecting more than one AncestryDNA test to your tree

See Activity 7 above.

12. DNA matches split up by parent

While AncestryDNA states this new feature is still in the testing stage, we've found it highly reliable and divides most matches by side without you needing to do anything other than identifying which is your paternal and maternal side.



Important note about unassigned matches from AncestryDNA: "If a match appears in this category, it could be because their test was processed after our last update (April 2022) or because we don't have enough information to assign them to one parent or the other.

You may see updates in the future, in which case some unassigned matches may be assigned to a side."

13. Privacy is in the tester's hands

Here are a few words from Ancestry on this important topic - Link to video.

When taking a DNA test, your test name will approve on the match lists of thousands of "DNA cousins" around the world. You should consider whether you want your known name or an "anonymised" name to be shown. You can change the test name at AncestryDNA under Settings on your DNA home page.

You can also choose not to be listed as an AncestryDNA match, but this option prevents you seeing your matches. Fortunately, the feature can be switched on and off, providing more control over your privacy. You can read more about this feature HERE.

Look at your AncestryDNA home page to check the name shown to matches and the person the test is linked to in public and private searchable trees. You can read about Ancestry's privacy philosophy HERE.

An important reminder - If you want to completely anonymise your AncestryDNA test, anonymise your name and don't link the test to a tree at Ancestry. Generally, you would only share your test results with others as a viewer. Careful consider who you give access to and the level to access you allow. Remember that they can see the same information at AncestryDNA as you can including notes and groupings.

14. How strong is the proof?


My view is that the standard of proof required depends very much on the situation. "Beyond reasonable doubt" is required for a parent/child relationship. The standard might lower to "balance of probabilities" for a two times great-grandparent. Remember that one 7cM match is "insufficient" proof of a relationship. This chart covers the evidence generally required based on the relationship to the tester.


Finally, remember that learning to work with DNA evidence takes time and effort. You can continue along the "DNA Pathway" offered by the Society of Australian Genealogists.

"Collecting Cahill Cousins" - A case study

You can listen to a thirty minute video I've recorded that shows how I've combined documentary and DNA evidence to expand my research on this line of my family HERE.

Recommended reading and podcasts-

Useful references-


Important note about unassigned matches from AncestryDNA: "If a match appears in this category, it could be because their test was processed after our last update (April 2022) or because we don't have enough information to assign them to one parent or the other.

You may see updates in the future, in which case some unassigned matches may be assigned to a side."

SAG's DNA activities

  • Check the events calendar HERE for upcoming events
  • For SAG members, check our the members area HERE for recordings of DNA stories at Hang Outs and Let's Talk about DNA

Other links

Please use the contact form on this blog for questions.

Popular posts from this blog

MODULE 2: Grouping your AncestryDNA matches - The Leeds Method and my "twisted" Leeds Method

MODULE 1: Working with AncestryDNA (Starting to solve your DNA dilemmas!)