Whether your oldest CASSIDY ancestor is a male or female, DNA testing can help to identify your ancestral Cassidy line. However, you may need to apply different DNA analysis techniques before you can confirm your Cassidy pedigree and to be confident of valid connections back to Ireland where most Cassidy's originate.
There are three DNA tests that might help depending on where your Cassidy sits in your pedigree:
* Autosomal-DNA test at AncestryDNA, Family Tree DNA, My Heritage or 23andMe - for both males and females whose ancestry is expected to be Cassidy on any of their ancestral lines;
* Y-DNA test at Family Tree DNA - for male CASSIDY's whose ancestry is expected to be Cassidy on their paternal line, ie. father, fathers father, fathers paternal grandfather, etc;
* mt-DNA test at Family Tree DNA - for both males and females whose ancestry is expected to be Cassidy on their oldest maternal line ancestor, ie.mother, mothers mother, mothers maternal grandmother, etc.
Is your line DNA confirmed?
Y-DNA tests can be expensive, particularly the best test - the Big-Y. So before you make an investment in these types of Y-DNA tests, make sure your Cassidy line appears to be DNA confirmed through autosomal testing first. Approximately 25% of DNA testers find there is a break in their line due to unexpected parentage events, adoptions etc.
The recommended strategy is:
* Test at AncestryDNA first and ensure you have DNA confirming your Cassidy line up to your 2nd great grandparents. AncestryDNA is particularly recommended for Americans and Australians due to the large numbers of testers from these countries. AncestryDNA has the largest database of DNA testers plus many family trees which helps to identify connections. Try to test all your older relatives who would have Cassidy DNA, male and female;
* Testers at AncestryDNA should upload their results to a chromosome analysis site to achieve the best results, particularly if you wish to confirm your pedigree beyond 2nd great grandparents. Refer to Louise Coakley's
Genie1 Blog for instructions;
* If you test at AncestryDNA, MyHeritage or 23andMe you can upload your results for free to GEDMatch, FamilyTreeDNA and LivingDNA which will assist in making more connections. Testing at FTDNA and LivingDNA can also enable you to upload to these sites but unfortunately you cannot 'transfer in' to either AncestryDNA, 23andMe or MyHeritage;
* Once your Cassidy line is confirmed through autosomal testing, test the oldest male CASSIDY ancestor at FTDNA for their Y-DNA. STR testing should be at least at the 37 marker level and up to 111 markers (if you can afford it). The Big Y is even more expensive but will provide details of SNP's which will better position your ancestor in the Haplogroup tree, ideally within the genealogical timeframe. Y-DNA testing can confirm ancestry back many thousands of years, much more than autosomal tests and is best for connecting more distant ancestors.
* Be careful when choosing a Y-DNA tester, if you are recruiting a more distant cousin for an expensive test like the Big-Y - make sure that autosomal results indicate that the families are likely to be related, ie associated cousins are matching through autosomal DNA.
CASSIDY Autosomal (au/at) DNA Testers
Testing your au/at-DNA can be undertaken at a variety of companies including AncestryDNA, My Heritage, FTDNA, LivingDNA and 23andMe. If you have tested your au/at-DNA which includes a Cassidy ancestor you should also:
* Use the FTDNA advanced matching tool to find other matches in the Cassidy project;
* Upload your results to
GEDmatch to connect with testers from other DNA testing companies;
* Join the GEDmatch Ancestors Project to find other matches in the Cassidy project. Under free tools on the GEDmatch homepage, search for Cassidy;
* Use the same file to other sites who accept free transfers - you may as well 'swim in all the ponds';
* Unfortunately you cannot upload results to AncestryDNA, 23andMe and My Heritage, you will need to test there;
* Instructions for downloading from AncestryDNA and uploading to other sites can be found
here.
CASSIDY Y-DNA Testers
Y-DNA tests can only be undertaken at
FTDNA. You should test at least 37 markers (up to 111), or do the Big-Y. For best results take the highest level test you can afford. You should also join projects and add your results to third party tools to maximise your connections and hopefully identify your oldest Cassidy patriarch:
* Use the FTDNA advanced matching tool to find other matches in the Cassidy project;
CASSIDY mt-DNA Testers
mt-DNA tests can only be undertaken at
FTDNA. If you have tested your mt-DNA which includes a Cassidy ancestor on your maternal line you should also join projects relevant to your mt-DNA haplogroup and add your results to third party tools to maximise your connections and hopefully identify your oldest Cassidy matriarch:
* Use the FTDNA advanced matching tool to find other matches in the Cassidy project;
Communicate with other CASSIDY cousins
Increase your chances of connecting with other Cassidy's
* Add your pedigree to a 'One World Tree' - we recommend
WikiTree;
Other information
As part of the recent 2022 Cassidy Clan Gathering in Fermanagh Ireland, I prepared two presentations that are now on You Tube. I hope you might find them of interest, both are approximately 30 mins each. The first focuses on the nuts and bolts of DNA testing, what, who and why you should test. The second focuses on my family and what I have been able to achieve through DNA testing.
More help
If you need help with Wikitree or other aspects in this post, please do not hesitate to contact me via the contact form on this blog, by private message at
Wikitree, or email cassidyclandna AT gmail.com.
Veronica Williams
First published: 21 June 2022
Last updated: 3 June 2026
