Your DNA - Another Vital Record!

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 "Collecting Cahill Cousins"

These notes accompany my presentation at the 37th Annual Conference of the NSW and ACT Association of Family History Societies on 16 September 2022. Others are welcome to use these notes for their personal research.  Please contact me at chrisw9953[at]gmail[dot]com for other uses. 

The presentation uses case studies to demonstrate how DNA has helped me unravel the family of my paternal grandfather, James Oswald Woodlands (1891 to 1946). In particular, to prove "beyond reasonable doubt" that his mother, Agnes, is the daughter of James Cahill and Eliza Dunn.

My aim is to encourage all participants to use both traditional research and DNA evidence so we don't miss any "vital" evidence. In 2022, genetic genealogy is an essential part of our family history toolbox.

You can register for another great DNA session presented by the Society of Australian Genealogists at 7.30pm on Thursday 24 November 2022 HERE.


The stories of five of the children named in the 1890 death certificate of Eliza Cahill (nee Dunn) will be used to show that paper based vital records, like birth, death and marriage certificates, can be inaccurate, incorrectly identified or missing but DNA doesn't lie. However, we must invest time and effort into understanding how to interpret our DNA results or we could misinterpret them.

One in four people who take a DNA test find a case of misattributed parentage between themselves and their great-grandparents. That's a 25% chance between you and your fourteen closest ancestors that you're not researching your biological ancestor. My grandfather didn't know his biological father. I research both my biological (or genetic) and known (or social) families.

My great-grandmother, Agnes Woodlands (nee Cahill) was one of the children named on the 1890 death certificate of Eliza Cahill (nee Dunn). Without being able to find Agnes's birth registration or baptismal record, DNA was my way of proving the Agnes was the child of Eliza and her husband, James Cahill.

James and Eliza arrived in NSW from County Kilkenny in 1855. They were newly wed and settled in the Hunter Valley around Branxton. James worked for the railways while Eliza raised their large family. James died in 1877 and Eliza died in 1890. If you're a descendant of James and Eliza, I'd love to hear from you.


Catherine married William Dries, Hannah married Charles Montague and Dominic Ceci, Bridget married William Antcliffe, Thomas was known as Thomas Carroll and Mary married Robert Wood. 

We're a small family but I work through what I find with my Cahill first cousins and half first cousin once removed. They've taken DNA tests to help my research and happily share our family stories.


Genetic genealogy has exploded since 2015:-
  • AncestryDNA has become the leading testing company since it entered the Australian market in 2015.
  • Currently, over 80% of Australians test at AncestryDNA and 25% of these people test or transfer to other testing sites and GEDmatch. 
  • My HeritageDNA is the second most popular testing site. 
  • There's been more than a 700% increase in testers in the last five years. 
  • Autosomal DNA tests are taken by over 99% of testers. 
  • More tools have become available to help analyse our DNA results.
DNA is essential evidence for all family historians to-
  • break down brick walls,
  • solve previously unsolvable mysteries and 
  • verify your paper trail.
Family historians are often searching for a "needle in a haystack". DNA can point you to the haystack. You might even find the needle.


You can read about the DNA testing strategy for Australians HERE. By testing and transferring, you are "fishing" for DNA matches "in all the ponds". Any of these DNA matches could be the key to solving your DNA dilemma.

Over the last few years, I've looked at the best way to go about our DNA research. Here I'm comparing AncestryDNA to the other testing sites. I find over and over that we get 80% of our DNA evidence with 20% of the total effort when working at AncestryDNA. Generally, AncestryDNA works well working back to the second or third great-grandparents in the early to mid 1800s. We're working with the total amount of DNA shared with our DNA cousins. Beyond this, we generally need to be working at the chromosome level. This is not supported by AncestryDNA. We need a strong foundation in working with total shared DNA before we move to the chromosome level.


I use the same methodology for resolving DNA dilemmas at AncestryDNA. This is a three prong approach of sorting matches into groups and identifying and tracking groups of DNA matches to find common ancestors. The process is iterative and I'm constantly interpreting and reviewing my findings. 


By using AncestryDNA groups to sort your matches, you can build on your known matches to work out the possible relationships with your unknown matches. This helps break down your brick walls. 

You can use whatever grouping suits you to sort your match but my tip is to be systematic. I sort all my fourth cousin and closer matches into the second great-grandparent lines that I (probably) share with them. I use a unique naming convention to help me be systematic.

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.


When we are working with a group of three or more 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. To prove a relationship "beyond reasonable doubt", we generally look for tree triangulation between, at least, three second or third cousins from different descendant lines. This is demonstrated in my presentations. 


My match with Margaret was my first evidence that Agnes was the child of James Cahill and Eliza Dunn. With tree triangulation between myself, Marg and Emma, I proved that Agnes was the child of James and Eliza "beyond reasonable doubt". While I haven't been able to find a birth registration or baptismal record for Agnes, she's named on Eliza's 1890 death certificate and James and Eliza are named as her parents on her 1901 marriage certificate. Also, I don't share any other ancestral lines with Marg or Emma within the timeframe of my traditional research.

Now for a few tips!

  • No contact from matches, doesn't mean no action. I use all the clues my "DNA cousins" leave me to find our link.
  • I also share stories in blogs, social media and public trees to record my findings and encourage engagement.
  • Remember to record information as it can disappear - your DNA match and/or their trees can be deleted or privatised.
  • Know your tree and know your matches as this is the key to breaking down brick walls. Grow your tree so that is broad and deep by including the siblings of your grandparents, great-grandparents etc and then research these down to the current generation.
  • Collaboration with your DNA cousins and others researching your families is another key to success. 
  • "Target" test cousins near and far to help your solve your DNA dilemmas.
  • Ask your DNA matches if they will share their AncestryDNA test results with you as a "collaborator". This allows you to "look through a different lens" as they may have matches that you don't because of the random way DNA is passes from parents to children. 

My presentation show ...

  1. We should all take a DNA test.
  2. We should think about asking relatives near and far to take a DNA test,  particularly those in earlier generations.
  3. We should test at AncestryDNA even if we've tested elsewhere.
  4. We should invest time and effort to develop our DNA research skills.

Why?

  1. Vital records can be inaccurate, incorrectly identified or missing.
  2. DNA doesn't lie.
  3. DNA can be misinterpreted.

DNA is the best way of pointing you to the haystack.

You might even find the needle.

Back in 2017, I was thrilled with my AncestryDNA match with Margaret as this was my first DNA evidence that James Cahill and Eliza Dunn were my great-great-grandparents. There's absolutely no question about it now. Five years on, you can see all those "DNA cousins" that I have on my Cahill/Dunn line!


If you're interested in finding out how to use DNA in your family history research, you can check out the event calendar for the Society of Australian Genealogists HERE. I regularly present sessions. You can add your name to the waitlist  for the "Analysing your AncestryDNA Program" HERE.

Click HERE for the full list of my DNA musings!

Dedicated to the memory of cousins
Robert, Margaret and Marjorie

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