First Look at AncestryDNA

Revised version: June 2025

Welcome to this comprehensive guide to working with your AncestryDNA results. These notes accompany the Society of Australian Genealogists’ webinar “First Look at AncestryDNA” and are intended to support individuals who are beginning to explore the use of autosomal DNA in their family history research. The content is regularly updated to reflect changes in available tools and improvements in understanding. If you would like to reuse this material beyond personal research, please contact me at chrisw9953[at]gmail[dot]com.

AncestryDNA offers a range of features that can assist researchers in identifying biological relationships, confirming lineages, and uncovering new connections. However, the effective use of DNA evidence requires more than just receiving test results - it involves a clear understanding of genetic concepts, thoughtful analysis and careful integration with documentary research.

To help you navigate, here’s a quick overview of what's covered:-

Update on Ancestry Subscriptions – What you and your matches can (and can’t) see
Setting the Scene – What autosomal DNA is and who shows up in your match list
DNA Terminology – What is a segment? What’s a centiMorgan?
What’s the Goal? – Defining your research questions and finding the MRCA
Full vs. Half Relationships – Why this distinction matters for your tree
MPEs, NPEs & Surprises – What they are, and how common they really are
Tree Triangulation – How to find shared ancestors using public trees
Two Trees: Genetic vs. Social – Using the right one for DNA research
Recombination & Match Variation – Why siblings match differently
Why testing more people helps
A Testing Strategy for Australians – Where to test and where to transfer
DNA as Proof of Pedigree – Turning your family story into evidence
What’s Your DNA Dilemma? – Why focus helps
Ethics, Privacy & Respect – Key principles when working with matches
Getting the Most from Your DNA Results – Where 80% of your insight comes from
DNA doesn't lie - but it can be misinterpreted
Working with AncestryDNA – Step-by-Step Activities
Tips & Techniques – Best practices for building and evaluating your genetic tree
How Strong Is the Proof? – DNA confidence levels by generation
Case Study: Collecting Cahill Cousins – A real-life example using DNA + documents
Chrome Extensions for DNA Research – Handy tools for your browser
Further Reading & Podcasts – Expand your knowledge and hear others’ stories
Useful References for AncestryDNA – Expert links and resources
SAG DNA activities
Other Popular Posts on This Blog
Final Words – DNA is a Journey – Keep going, keep learning

1. Update on Ancestry Subscriptions

If you're using AncestryDNA, it’s important to understand how subscriptions affect what you and your matches can see.

🧬 Most of your DNA matches won’t have a subscription - which means they can only see limited information about their matches including you. That can make it harder for them to figure out how you're related.

✅ If you don’t have an Ancestry subscription yourself, consider AncestryDNA Plus. It’s a lower cost option at $39.99 every six months, giving you access to useful tools and features designed specifically for DNA users. You can read more about what’s included HERE.

🔍 Ancestry Pro Tools is available to those with a full membership. It gives you access to advanced DNA and family history tools.

Pricing for Pro Tools may vary. I currently pay $10 USD per month. You can learn more HERE and subscribe if it suits your needs.

(Prices are current as at June 2025.)

2. Setting the scene

The four types of DNA: Autosomal, mitochondrial, Y-DNA, and X-DNA. Each tells a different part of your genetic story. [Read more HERE]

What AncestryDNA tests: Autosomal DNA (atDNA), sometimes called “cousinship DNA” - because it helps identify relatives across multiple lines.

How autosomal DNA is inherited: The further back an ancestor is, the smaller the chance you inherited any DNA from them. That’s why shared DNA with matches get smaller with distance. [Read more HERE]

Who appears in your match list: You’ll typically see all your 2nd cousins, about 98% of 3rd cousins, and fewer beyond that. [Read more HERE]

3. DNA terminology

Segment
A segment is a continuous piece of DNA that’s measured in centiMorgans (cM). Segments are:

Inherited from your ancestors
Shared with your DNA matches

However, not all shared segments are equally useful. Some small segments may be coincidental and not traceable to a common ancestor. What we’re looking for are shared segments passed down from a known or likely common ancestor.

centiMorgan (cM)
A centiMorgan is the unit used to measure genetic distance - created by scientists and used by all the major DNA testing companies.

👉 The more cM you share, the closer you're likely to be related.

4. What’s the goal?

Your aim in working with DNA matches is to figure out how you're related. That relationship is defined by your most recent common ancestor(s)—commonly referred to as the MRCA.

If you and your match descend from the MRCA by different numbers of generations, the cousin relationship is “removed” by that difference. Read more HERE and explore the ISOGG Cousinship Chart for help.

For example:

2nd cousins share the same great-grandparents.
If one person is one generation further down, they become 2nd cousins once removed.

5. Full vs. half relationships

You typically share about half as much DNA with a half cousin or half sibling compared to a full one.

Full relationships

You are in a full relationship with someone when you share both ancestors in a couple. For example:

Full siblings share both parents.
First cousins share both grandparents (they are the children of full siblings).
Second cousins share both great-grandparents.

Half relationships

You are in a half relationship when you share only one ancestor in a couple. For example:

Half siblings share only one parent.
Half first cousins share only one grandparent (their parents are half siblings).
Half second cousins share only one great-grandparent.

💡 Why it matters

Knowing whether a match is a full or half relative can help narrow down which side of the family to look at.
It’s especially important when building or verifying your genetic family tree.
Unexpected half relationships often point to MPEs or NPEs—surprises revealed through DNA.

You can also read more HERE about full vs. half relationships.

6. MPEs, NPEs & surprises

In genetic genealogy, you may come across terms like:

MPE – Misattributed Parentage Event
NPE – Non-Paternal Event
Or simply, misattributed parentage

These are used when a DNA result reveals an unexpected relationship - for the tester and/or one of their ancestors.

📊 Surprisingly common: Studies show that around 1 in 4 testers report an MPE between themselves and one of their great-grandparents - a 25% chance among your 14 closest ancestors.

7. What is tree triangulation?

Tree triangulation is a method used in genetic genealogy to help identify a most recent common ancestor (MRCA) shared by multiple DNA matches. Rather than comparing DNA segments (as in segment triangulation), tree triangulation focuses on comparing family trees.

🔍 How it works

Start with a group of DNA matches who all share DNA with you and with each other.
Build or examine their family trees - or research their ancestors using public trees, records or hints.
Look for overlap - a shared ancestral couple or family line that appears in all the trees.
That shared ancestor is your leading candidate for the MRCA.

🧩 Why it’s useful

It helps identify unknown ancestors when your own tree has gaps.
It’s especially powerful when working with matches who haven’t built full trees themselves.
It’s a practical method when you don’t have access to segment data (e.g. at AncestryDNA, which doesn’t offer a chromosome browser).

✅ Key tip

Tree triangulation works best when:

Your matches are from different branches of the same ancestral couple.
You confirm the paper trail with DNA evidence from multiple relatives.
You’re aware of possible complications like MPEs (misattributed parentage events).

8. Two trees: Genetic vs Social

Many of us have two family trees:

Genetic (biological) – the one that matters for DNA research
Social (known/raised by) – still important, especially for personal history

When doing DNA analysis, it’s your genetic tree that counts. It reflects the biological connections that DNA reveals.

9. Recombination – Why matches vary

Recombination is an essential (but tricky) concept in genetic genealogy. It’s the process by which each parent passes down a random half of their autosomal DNA to each child.

Australian genetic genealogist Louise Coakley offers one of the clearest explanations of recombination on her website. I recommend that you sign up for her newsletter HERE

"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."

10. Why testing more people helps

Because of recombination, who you test matters. Test widely—siblings, cousins, distant relatives—because you never know who inherited the key DNA segment that connects to an unknown match and breaks down a brick wall.

Take my own experience:

I share only 7cM with my 3rd cousin Vicki at AncestryDNA.
But I share 100cM with our other 3rd cousin Sue, while Vicki shares 21cM with Sue.
With another cousin, Les, I share 30cM - but Vicki shares 147cM.

That’s recombination in action! We all descend from the same couple, John Killion and Jane Feeney, but we share very different DNA segments from our MRCA.

11. A testing strategy for Australians

Start with AncestryDNA. It holds the biggest pool of Australian testers (27 M worldwide).
Export your raw DNA to GEDmatch, MyHeritage and FTDNA for free cousin‑fishing. [Read more HERE]
Upload results to Ancestry? Impossible - so test at Ancestry first.

For a deeper discussion see Testing Strategy for Australians on this blog.

12. DNA as "proof of pedigree"

DNA is now essential evidence for family historians who want to prove their pedigree—that is, confirm that every person in their tree is a biological ancestor, not just a name drawn from stories or unverified records.

How far can atDNA take you?

With autosomal DNA (atDNA) and your AncestryDNA matches, you can usually confirm relationships:

Parents to 2nd great-grandparents
Up to 3rd-cousin level

Beyond those generations, proof becomes more challenging and often requires:

Advanced DNA techniques (segment triangulation, chromosome mapping)
Tools and segment data not available at AncestryDNA alone
Additional testing platforms (e.g., FamilyTreeDNA, MyHeritage, GEDmatch)

🧬 Why “prove your pedigree”?

"Proving your pedigree" confirms that the people in your family tree are your biological ancestors - not just names based on assumptions, family stories, or records alone. It’s about turning a theoretical tree into a documented one, backed by reliable evidence.

🔎 What counts as proof?

DNA Evidence - DNA can confirm genetic relationships, especially when:
- You match known relatives in expected ways
- Shared matches help identify common ancestors
- CentiMorgan (cM) amounts support the proposed connection
Documentary Evidence - Traditional records like:
- Birth, marriage, and death certificates
- Census and immigration records
- Wills, obituaries, and church registers
A Strong Paper Trail + Genetic Support
The gold standard is when DNA and documents both point to the same ancestor.

✅ Why it matters

It helps verify your research is accurate.
It prevents you from following the wrong ancestral line.
It provides credible evidence when sharing your findings with others.

In short, proving your pedigree moves your family history from possible to provable.

13. What’s your DNA dilemma?

Before diving into your matches, take a moment to define your research goal. What question are you hoping DNA can help you answer?

This focus will help you-

clarify what kind of evidence you’re looking for,
identify which relatives to test for the best chance of solving your puzzle and
make better use of your DNA matches.

Check out Danielle Lautrec’s Research Planning with DNA – a practical resource to help you build a DNA strategy for your family history research.

14. Ethics, Privacy & Respect

As with all family history work, it’s important to consider the privacy and rights of others when using DNA. Key considerations are-

contacting DNA matches respectfully,
recording and sharing DNA findings sensitively and
asking others to test with clear information and consent.

You can read the Society of Australian Genealogists' code of conduct and protocols HERE.

15. Getting the most from your DNA results

The more I work with genetic genealogy, the more I’ve come to see a clear pattern. We get about 80% of our DNA evidence with just 20% of the effort when we know how to make the most of our AncestryDNA results (and, to a lesser extent, MyHeritageDNA). This approach is especially effective for confirming connections from your parents through to your 2nd or 3rd great-grandparents - usually covering ancestors from the early to mid-1800s.

➡️ When to move beyond AncestryDNA

I recommend that you "move to the right-hand side" (into more advanced methods and tools) only after:-

You have a strong understanding of the techniques needed to work with AncestryDNA.
You’ve fully explored all the insights available from your matches there.

This session is just the beginning of that journey.

🧠 Want to Go Further?

If you're ready to deepen your skills, the Society of Australian Genealogists’ program “Analysing Your AncestryDNA Matches” covers these advanced techniques in more detail. You can register your interest by emailing admin@sag.org.au.

16. DNA doesn’t lie - but it can be misunderstood

DNA is powerful evidence, but to use it well, we must invest time in understanding how it works and how to interpret it accurately. Misinterpretation is easy without a clear grasp of the basics.

To support this session, I’ve recorded a 30-minute presentation titled:

🎥 "Your DNA – Another Vital Record"

In it, I walk through how I’ve used atDNA to answer key questions in my Cahill ancestral line. You can watch the presentation HERE.

17. Activities to help you work effectively with AncestryDNA

In the next section, you’ll find step-by-step activities designed to help you become familiar with AncestryDNA’s layout and navigation. These practical tasks will introduce you to the core features you’ll use regularly and set you up to work more confidently and effectively with your DNA results.

🛠️ Help is at hand

AncestryDNA includes many built-in links to its comprehensive Help pages. You can also browse them directly HERE.

For an additional resource, download the excellent (though slightly dated) DNA Guide by DNA Adoption HERE. Note: Last updated in July 2021, but still full of helpful tips.

These hands-on tasks will help you understand and make the most of your AncestryDNA results. Click the provided links for step-by-step guidance.

🧬 Your DNA test & tree setup

Check your public profile – especially which trees are viewable.
🔗 [Instructions HERE]
(Tip: You may have multiple trees, but your DNA test can only be attached to one tree. On the other hand, multiple tests can be attached to one tree.)
Is your DNA test linked correctly to a public or private searchable tree?
🔗 [Instructions HERE]
Tree settings - ensure "Your home person in this tree" and "Who you are in this tree" are set to the tester.
🔗 [Set Home Person HERE] | [Set Yourself in Tree HERE]
(These can be changed if you’re working with someone else’s kit.)
Split your matches into Parent 1 and Parent 2 groups (maternal/paternal).
🔗 [Instructions HERE]

👥 Managing access & privacy

Why share your AncestryDNA results?
🔗 [Share Results Instructions HERE]
🔗 [Access Another Test on Your Account HERE]
Why download your raw DNA data?
🔗 [Download Instructions HERE]

🌳 Tree view & ethnicity

In the pedigree view, ensure biological ancestors are shown and DNA icons are turned ON as shown in the first image.
Compare your ethnicity expectations to your AncestryDNA estimates. Then review your Ethnicity Inheritance by parent.

🔗 Working With Matches

Can you connect a DNA match to your tree?
🎥 [Watch video – first 8 minutes covers this HERE]
Add relationships to your top three known DNA matches.
🔗 [Instructions HERE]
Use filters and sort tools:
- View unviewed matches with Common Ancestors
- Sort by date and filter for close matches
- How many close matches appeared in the last 7 days?
  🔗 [Instructions HERE]
Learn about grouping and filtering your matches.
🔗 [Read HERE]
🎥 [Watch my 30-minute video on the Leeds Method + “Twisted” Leeds HERE]

🏷️ Tags, Hints & ThruLines

Tag your matches and ancestors using MyTreeTags:
- Add a "DNA Match" tag to your closest known match (not your child/grandchild)
- Add a "Common DNA Ancestor" tag to your MRCA
- Use "DNA Connection" tags if needed to connect them
  🔗 [Read about MyTreeTags HERE]
Explore ThruLines:
- Filter for "Potential Ancestors"
- Review your top two—look for clues, but always evaluate, evaluate, evaluate
  🔗 [Learn about ThruLines HERE]

18. Tips & techniques for working with AncestryDNA

“Know your tree and know your matches.”

Use these best-practice steps to move from raw data to reliable evidence.

1. Who should you test to solve your DNA dilemma?

Guideline	Why it matters
Test the oldest living generation first.	They carry larger, less-diluted segments.
Analyse parents before children.	They share more DNA with matches and have more matches
If only one parent is available, test every child.	Siblings inherit different DNA; together they cover more of the missing parent.
Can’t test a parent? Test their siblings or nieces/nephews.	They share much of the same DNA as the missing parent.
Include full & half cousins, near and far.	They help map both sides of each ancestral couple.
Request collaborator or manager access	Direct kit access speeds analysis and lets you add notes, groups, and tags.

2. Working through your match list

Start with your largest shared-cM match (or the largest in a cluster).
Confirm the relationship - DNA doesn’t lie, but records sometimes do.
Prove your pedigree generation by generation, beginning with your parents.

3. Contacting a match with no tree

Leverage shared matches to infer a possible common line first.
Message promptly (response rates drop over time).
Suggest the surname or ancestor you think you share and ask whether they:
- Have a public tree, or
- Can share birth/marriage dates & locations for their grandparents.
Supplement with public sources (social media, obituaries, electoral rolls) when matches don’t reply.

4. Link your test to a tree

Link to a public or private searchable tree—even a simple pedigree.
Use your genetic tree, not a purely social/adoptive tree.
Add researched “floating” or “hanging” branches when a match family is known but the link to the tester is unproven. [Learn more HERE]

5. Sharing Tests

Shared access offers another lens on relationships and may reveal new matches.
A tester without an Ancestry subscription can appoint you as viewer, manager or collaborator.
[Learn more HERE]

6. Custom groups to sort/cluster your matches

Sort/cluster systematically (e.g. by confirmed ancestor, colour-coded lines, or Leeds-style clusters).
Revise groups as needed—they can be renamed or deleted anytime.
Alphabetical surname groups rarely work - use genetic evidence instead.
Resources:
- My “grouping” approach [Blog post 1 HERE, Blog post 2 HERE, Blog post 3 HERE].
- 30-min video: Leeds Method + “Twisted Leeds” [HERE].
- Chrome extension - Genealogy Assistant [video | extension].
- Ancestry blogpost on clustering [HERE].

7. Add “Hanging Branches”

Create a provisional branch for a match when the exact link to the tester is unknown. Over time, use new evidence to connect it to your main tree. [More on hanging branches HERE.]

8. Build “Quick & Dirty” (Q&D) research trees

Private, unsearchable trees that gather records fast.
Ideal for adoptee cases or tricky mysteries. [How-to guide HERE.]

9. Remember - Shared matches ≠ Shared ancestor

Shared-match lists group people who share DNA with you, not necessarily with each other. Always verify with using tree triangulation and documentary evidence. [More HERE.]

10–11. Multiple tests & DNA relationships

Ensure DNA relationships are connected to the correct profile (see Activity 7).
You can link multiple tests to your tree—one per tree profile (see Activity 2).

12. SideView - Matches split by parent

Ancestry’s Parent1/Parent2 split is highly reliable once you identify which side is which.
Unassigned matches may be from which have been processed after the last update or lack enough data to assign a side—expect updates over time.
[Read more HERE.]

13. Privacy is in the tester’s hands

Decide whether to display your full name or an alias on match lists.
You may opt out of being shown as a match (and opt back in at any time). [Read more HERE.]
For full anonymity: use an alias and don’t link the kit to a public tree; share results only as Viewer.
Review Ancestry’s privacy philosophy HERE.

19. How strong is the proof?

My view is that the standard of proof required depends very much on the situation. Not all genealogical conclusions need to meet the same level of certainty. Here are some general guidelines I follow when evaluating DNA evidence in family history research:-

🧬 Parent–Child Relationship

Standard: Beyond reasonable doubt

Direct testing is expected
DNA evidence should be strong and unambiguous (typically 3,400+ cM)
Supported by consistent documentary evidence

👵 Grandparents and Great-Grandparents

Standard: Very strong confidence

Requires multiple DNA matches in the expected cM range
Matches should form a clear cluster
Should align with traditional records (births, marriages, census, etc.)

🧓 2× Great-Grandparents

Standard: Strong probability

DNA match groups typically in the 90–250 cM range
Consistency across multiple testers
A documented paper trail adds weight

👴 3× Great-Grandparents and Beyond

Standard: Balance of probabilities

Evidence may rely on distant matches (40–90 cM)
Clustered relationships supported by tree triangulation or segment evidence (if available)
Always requires careful evaluation and should be flagged as "hypothesis" if not conclusive

⚠️ Caution with Small Matches

Matches below 7 cM are generally not reliable as standalone evidence
Should always be supported by additional matches with documents
May indicate a real relationship—or just a coincidental segment

In all cases, I aim to combine DNA evidence with documentary research. When both align, I have the highest confidence in the accuracy of the connection.

20. Case study: “Collecting Cahill Cousins”

Watch a 30-minute walkthrough combining traditional research with autosomal DNA (atDNA) to reconnect descendants of my 2× great-grandparents, James Cahill and Eliza Dunn.
This case study demonstrates the power of using DNA evidence alongside historical records to uncover and confirm family connections.

🎥 View HERE

21. Useful Chrome extensions for genetic genealogy

Enhance your research workflow with these handy tools:-

🔘 Click All Checkboxes
Speeds up bulk actions (e.g. selecting groups of DNA matches on AncestryDNA).
👉 Great for clustering and tagging efficiently.
🧬 Genealogy Assistant
Offers quick access to research tools, records and AI helpers directly from your browser.
👉 A helpful sidekick for both DNA and traditional genealogy.
🫥 Genealogy Blurring Tool
Blurs names and private details on screenshots of trees, matches or charts.
👉 Ideal for preserving privacy when sharing visuals online or in presentations.

22. Further reading & podcasts

Explore the world of DNA, identity and family history through these books and audio stories:-

📖 Books - fiction and true stories

The Foundlings & The Deserter's Tale
by Nathan Dylan Goodwin
DNA mystery meets family history fiction.
🔗 Read more
Venator Cold Case Series
by Nathan Dylan Goodwin
A gripping blend of crime, cold cases, and investigative genetic genealogy.
🔗 Explore the series
I Know Who You Are
by Barbara Rae-Venter
The pioneer behind the Golden State Killer case tells her story.
🔗 Find on Amazon
The Forever Witness
by Edward Humes
A riveting account of how genetic genealogy solved a 30-year-old double murder.
🔗 Find on Amazon
Tell No One
by Brendan Watkins
An Australian story of adoption, secrecy, and family search through DNA.
🔗 Visit site
The Accidental Archivist
by Angela Bier
One woman’s journey into genetic genealogy, archival research, and unexpected family discoveries.
🔗 Find on Amazon AU

🎧 Podcast

The Gift – BBC Sounds
A thoughtful podcast series exploring the impact of unexpected DNA discoveries.
🔗 Listen on BBC Sounds

23. Useful references for working with AncestryDNA

Expand your knowledge with these expert articles and videos covering key AncestryDNA features and strategies:

🧬 DNA Tools and Features

AncestryDNA: DNA matches split by parent
Learn how Ancestry’s SideView technology helps divide your matches into maternal and paternal sides.
🔗 Read Article
The DNA Geek – SideView Explained
Leah Larkin (The DNA Geek) provides a detailed breakdown of how Ancestry’s SideView works and what it means for your research.
🔗 Read Article
Dana Leeds – Enhanced Shared Matches
Dana Leeds, creator of the Leeds Method, explains how Ancestry’s updated shared matches feature works.
🔗 Watch on YouTube

🎥 Crista Cowan (Ancestry’s corporate genealogist)

Making the most of your AncestryDNA match list
Practical tips to help you work more efficiently through your matches.
🔗 Watch on YouTube
Ancestry Pro Tools explained
Understand how Pro Tools add power to your match analysis.
🔗 Watch on YouTube
Cleaning up your family tree
Advice for tidying and correcting your family tree so it supports your DNA research effectively.
🔗 Watch the tutorial

24. SAG’s DNA activities

Looking to expand your DNA skills and stay connected with the community?

📅 Check the Events Calendar
Stay up to date with upcoming DNA webinars, workshops and special events.
🔗 [View upcoming events HERE]
👥 For SAG Members
Access recorded sessions including DNA Stories shared at Hang Outs and the Let’s Talk About DNA series.
🔐 [Visit the Members Area HERE]

25. Other useful posts from my blog

Explore more resources to support your DNA and family history journey:-

🌳 Let’s Talk Tree Terminology
Demystifying common terms like pedigree, genetic vs. social tree and more.
🔗 [Read the post]
📜 Purchasing NSW, VIC, and QLD BDM transcripts
Tips on ordering birth, death, and marriage records from Australia’s key states.
🔗 [Read the post]
🧬 How your DNA can help identify human remains and solve cold cases
An overview of forensic genetic genealogy and real-world impact.
🔗 [Read the post]

26. Keep going - DNA is a journey

Finally, remember that working with DNA evidence takes time, patience and practice. The skills you build will grow with each match you explore and every ancestral mystery you tackle.

You don’t have to do it alone - you can continue your learning through the “DNA Pathway” offered by the Society of Australian Genealogists. It’s a structured program designed to help you develop confidence and competence in using DNA evidence in your family history research.

📚 To learn more or register your interest, visit the SAG website or contact admin@sag.org.au.

🔍 Keep asking questions. Keep learning. And keep building your genetic family tree—one match at a time.

For questions or feedback, please use the contact form on this blog.